Lie.  ..^?vY 

UNUrlSITY  Of 
CALIfORHIA 


^ 


r 


/ 


€. 


OPTICAL  TRUTHS 


Second  Edition 


ILLUSTRATED 


By  CHARLES  McCORMICK,  M.  D. 

President  McCormick  Neurological  College 

The  First  Non-Sectarian  Medical  School 

CHICAGO 


Published  by 

McCORMICK  NEUROLOGICAL  COLLEGE 

Chicago 


OPTOMETRY  LIBRARY 


Copyright  1898,  by 
Charles  McCormick 


Copyright  1906,  by 
Charles  McCormick 


H.  P.  Springs,  Printer 
1632  Wabash  Ave.,  Chicago 


INTRODUCTION. 

In  the  practice  of  ophthalmology  one  of  the  essentials  is  a 
general  knowledge  of  the  nervous  system,  what  it  is,  whence 
it  cometh,  and  whither  it  goeth. 

It  is  simply  a  complete  telegraph  system,  intimately  con- 
necting every  portion  of  the  anatomy. 

In  structure  it  is  a  series  of  tubular  membranes  containing 
in  a  minute  and  continuous  stream,  matter  identical  with  the 
brain  substance,  through  which  electrical  energy  is  trans- 
mitted. 

This  energy  is  of  two  kinds,  galvanic  and  faradic.  The 
first  is  generated  by  the  digestive  organs,  and  is  constant ;  the 
second,  is  an  intermittent  current  generated  by  molecular  fric- 
tion throughout  the  body. 

The  nervous  system  is  divided  into  two  classes,  the  cere- 
bro-spinal  or  animal,  and  the  sympathetic  or  organic. 

There  are  two  currents  of  nerve  force.  The  afferent, 
from  the  peripheral  parts  to  the  nerve  centers,  and  the  effer- 
ent, from  the  nerve  centers  to  the  peripheral  parts. 

The  brain  is  the  chief  nerve  center.  "All  force  is  sent 
there,  and  thence  distributed  in  every  direction  and  in  such 
proportions  as  conditions  require.  To  do  this  the  brain  gives 
off  twelve  pairs  of  cranial  nerves  and  the  spinal  cord,  the 
latter  being  the  grand  trunk  line  which  supplies  the  minor 
centers  in  the  body. 

In  normal  physiological  conditions  the  distribution  of 
nerve  force  is  proportionate  to  the  capacity  for  supply,  and 
Nature  has  so  arranged  that  the  brain  contains  a  reserve  stock 
for  emergencies.  Were  it  not  for  this  wise  provision  the  sus- 
pension or  decrease  in  capacity  of  the  source  of  supply  would, 
surely  and  speedily,  result  in  death. 

In  youth  the  quantity  of  reserve  force,  as  well  as  the  ca- 


.'>m;i 


6  OPTICAL  TRUTHS. 

pacity  for  supply  is  greater,  hence  the  more  speedy  recovery 
from  injuries  and  ills.  Extraordinary  drain  upon  the  nerve 
supply  can  be  endured  without  discomfort,  because  of  these 
conditions.  When,  however,  the  reserve  supply  is  exhausted, 
the  demand  is  made  directly  upon  the  capacity  of  the  machin- 
ery and  trouble  follows. 

Any  abnormal  physiological  condition,  or  functional  de- 
mand which  requires  more  than  the  normal  proportion  of  nerve 
force  in  one  direction,  will  have  evil  effects  upon  other  func- 
tions as  soon  as  the  reserve  is  reduced  below  the  safety  line. 
One  of  these  is  the  intense  thought  associated  with  grief,  joy, 
fear,  anger  and  other  emotions,  because  the  demand  is  directly 
upon  the  chief  source  of  supply. 

In  this  connection  it  is  interesting  to  note  by  experiment, 
the  effect  of  thought  upon  the  various  functions.  The  phe- 
nomena of  blushing,  turnuig  pale,  etc.,  are  illustrations  of  the 
influence  of  thought  upon  the  nerves  which  control  the  circula- 
tion 01  blood. 

The  influence  of  the  mind  upon  the  body  is  being  recog- 
nized by  the  medical  colleges  of  today,  and  psychology  is  one 
of  the  special  branches  taught.  The  Faith  Healers  find  the 
basis  for  their  work  in  the  same  proposition,  coupled  with  a 
fanatical  belief  that  they  are  especially  endowed  by  God. 

Each  case  which  presents  itself  to  the  ophthalmologist  has 
individual  peculiarities,  and  only  a  thorough  knowledge  of 
elementary  principles  of  anatomy,  physiology,  neurology, 
physics,  psychology  and  mathematics  will  enable  the  practi- 
tioner to  meet  them  with  credit  to  himself  and  comfort  to  hia 
patients.  He  must  also  cultivate  his  common  sense,  and  look 
for  the  simplest  way  out  of  any  difficulties  which  may  arise. 

In  the  following  pages  the  author  endeavors  to  give  infor- 
mation, accompanied  by  practical  reasons  for  each  proposition, 
and  trusts  it  will  be  of  service  to  all  into  whose  hands  it  may 
come. 

This,  second  edition,  is  issued  in  response  to  continued 
demands  since  the  first  one  was  exhausted  two  years  ago. 


LIGHT  AND  REFRACTION. 

Elementary  Laws  Which  Reveal  the  Breadth  and  Compre- 
hensiveness of  Nature. 
Everything-,  to  our  minds,  educated  by  finite  things,  must 
have  a  beginnings — and  an  end.  Therefore,  let  us  imagine  that 
there  was  a  beginning  to  this  universe;  that  it  is  the  effect  of 
a  cause.  It  is  a  well-settled  proposition,  except  among'  fanat- 
ics, that  we  shall  never  conceive  in  what  form,  if  any,  that 
cause  existed  or  exists,  other  than  as  we  refer  to  it  as  an 


8  OPTICAL  TRUTHS. 

infinite  mind,  instead  of  as  a  person.  To  me  the  law,  as  ex- 
hibited in  its  effects,  is  far  more  magnificent  than  an  individual 
could  be  possibly. 

It  is  our  privilege  to  study  the  laws,  if  we  will,  independ- 
ently of  accepted  authorities;  and  when  we  see  how  far  some 
have  strayed  from  the  facts,  which  came  to  light  after  their 
theories  were  exploited,  we  are  admonished  to  avail  ourselves 
of  the  privilege. 

As  the  refraction  of  light  is  one  of  the  primary  lav/s  by 
which  ophthalmology  is  expounded  in  this  work,  it  is  necessary 
to  define  light  and  I  choose  the  following  hypothesis  as  a  be- 
ginning : 

Let  Fig.  1  represent  the  universe,  the  large  central  field 
the  sun,  the  small  dots  the  planets.  In  the  operation  of  the 
chemical  laws  combination  and  disintegration,  attraction  and 
repulsion,  form  and  motion  were  produced.  Within  a  certain 
space  the  positive  and  negative  qualities  of  each  planet  are 
supreme,  so  they  maintain  their  respective  distances  from  each 
other,  yet  there  is  one  grand  center  about  which  they  all 
revolve.  The  chemical  product,  or  the  friction  from  motion, 
or  both,  generates  what  is  known  as  electricity.  First  the  cen- 
tripetal effect  is  to  overcharge  the  center,  when  a  centrifugal 
reaction  obtains  and  we  have  the  duality  complete  in  positive 
and  negative  magnetic  currents.  The  lines  in  the  figure  show 
only  the  negative  ones,  that  is,  those  from  the  sun,  and  only  a 
few  of  them.  The  sun  being  as  large  in  comparison  with  the 
planets  as  the  center  field  is  larger  than  the  dots  it  is  easy  to 
see  how  these  currents  reach  all  the  planets,  all  the  time,  ex- 
cept when  occasionally  one  planet  gets  in  the  way  of  another 
enough  to  shut  off  the  currents  from  a  small  portion  for  a 
short  time,  as  is  illustrated  by  eclipses.  This  electricity  reaches 
us  in  the  form  of  a  luminous  force  and  not  only  enables  us  to 
see  objects  not  luminous  themselves,  but  it  also  vitalizes  the 
earth,  making  it  habitable  and  productive. 

Some  writers  have  asserted  that  there  is  no  such  thing'  in 
nature  as  a  convergent  ray.     I  concede  the  point  and  assert, 


LIGHT  AND  EEFRACTION. 


further,  that  there  is  no  such  thing  as  a  diverg-ent  ray.  It 
requires  two  or  more  rays  to  exhibit  convergence  or  diverg- 
ence, and  when  we  have  a  multitude,  as  we  have  from  the 
sun,  there  are  both  convergence  and  divergence,  as  is  shown 
in  the  figure.  Of  course  when  we  look  at  a  small  object 
some  distance  away  the  rays  we  receive  in  the  pupil  of  the 
eye  are  divergent  from  each  other  as  they  radiate  from  the 
same  points;  but  as  the  pupil  is  only  about  one-eighth  of  an 
inch  in  diameter  the  rays  enter  it  so  nearly  parallel  that  they 
are  assumed  to  be  exactly  so  in  our  calculations. 

Refraction  is  the  deviation  in  its  course  a  ray  of  light  suf- 
fers in  passing  obliquely  from  one  transparent  medium  to 
another  of  different  density. 

The  amount  of  refraction  is  governed  by  a  duality,  the 
angle  of  incidence  and  density  of  medium;  it  is  measured  ac- 
cording to  natural  laws. 


Let  the  line  R  S,  Fig.  2,  represent  a  ray  of  light  passing 
obliquely  through  air ;  it  suffers  no  change  in  its  course  at  the 
line  C  D,  because  there  is  no  change  in  the  density;  there- 
fore, the  angles  1  and  2  formed  by  the  ray  with  the  line  A  B, 
are  of  equal  size.  Air  being  the  medium  throug-h  which  all 
light  comes  before  it  can  pass  any  other,  and  being  the  rarest 


10 


OPTICAL  TRUTHS. 


of  all,  it  is  taken  as  the  standard  or  unit  of  density,  that  is, 
of  resistance  to  the  passage  of  light,  and  all  other  mediums 
are  compared  with  it,  the  ratio  they  bear  to  it  respectively  is 
called  their  index  of  refraction. 

The  first  thing  required  for  the  purpose  of  measurement 
of  the  amount  of  refraction  is  a  line  drawn  perpendicular  (at 
right  angles)  to  the  surface  under  consideration.     If  the  sur- 


CLiA  100 


V/^-ttr  /.Si^ 


Ci^  \M 


face  is  horizontal,  the  perpendicular  will  be  vertical;  if  the 
surface  is  oblique  the  perpendicular  will  be  oblique  also.  An 
easy  way  to  locate  the  perpendicular  is  to  make  the  point 
where  the  ray  strikes  the  second  medium  the  center  of  a  circle 
and  put  the  perpendicular  90  degrees  from  the  surface.  Thus, 
if  the  surface  is  at  an  angle  of  45  degrees  the  perpendicular 
will  be  at  135  degrees.     Or  if  the  surface  is  at  120  degrees  the 


LIGHT  AND  REFRACTION.  tt 

perpendicular  will  be  at  30  degrees.  All  degrees  are  numbered 
from  the  horizontal  and  begin  at  the  right.  All  measurements 
are  at  right  angles  to  the  perpendiculars,  and,  as  the  denser 
the  medium  the  slower  the  speed  and  the  rarer  the  medium 
the  greater  the  speed  at  which  the  ray  travels,  it  follows  that 
in  measuring  angles  we  must  reverse  the  figures,  therefore,  if 
we  bear  in  mind  that  we  have  only  two  sizes  of  angles  and  the 
small  one  is  always  in  the  denser  of  the  two  mediums  it  will 
be  easy  to  master  the  very  necessary  preliminEiry  work  quickly. 

Fig.  3  shows  what  would  occur  if  a  ray  from  R  should 
come  in  contact  with  a  body  of  water  at  the  point  where  it 
crosses  the  line  A.  Its  course  would  be  changed,  for  the  rea- 
son that  its  movement  is  swifter  in  the  rare  medium,  and,  its 
lower  side,  meeting  the  obstruction  first,  would  be  retarded  in 
its  progress,  while  the  upper  side  would  continue  its  speed, 
thus  gaining  on  the  other,  so  that  the  course  of  the  ray  through 
the  denser  medium  would  be  toward  D  instead  of  in  the  direc- 
tion of  C.  As  it  passes  obliquely  through  the  water,  it  will  be 
seen  the  lower  side  would  be  released  first,  and,  renewing  its 
original  pace,  would  gain  on  the  other  side,  recovering  what 
it  had  lost  at  the  first  surface,  and  would  pass  toward  E,  par- 
allel to  but  not  on  the  line  of  its  original  course. 

From  the  amount  of  deviation  as  shown  by  the  propor- 
tions of  the  angles  formed  in  the  two  mediums,  we  learn  the 
relative  density,  4  is  to  3  as  1.33  1/3  is  to  1.00,  therefore  the 
index  of  refraction  of  water  is  133  1/3.  If  we  substitute  glass 
for  water  we  would  have  angles  proportioned  as  3  is  to  2, 
hence  the  index  of  glass  is  1.50.  If  we  could  substitute  dia- 
mond the  angles  would  be  as  5  is  to  2,  hence  the  index  of  dia- 
mond is  2.50. 

According  to  its  index  of  refraction  water  would  cause 
the  ray  to  change  its  course  so  that  the  angle  formed  by  the 
ray  and  the  vertical  line  at  3  would  be  in  proportion  to  that 
formed  by  the  ray  and  vertical  line  at  the  same  distance,  4, 
above  the  first  surface,  as  1  is  to  1.33  1/3. 

The    same    law  applies  in  passing  from    the    dense  to 


12 


OPTICAL   TRUTHS. 


the  rare  medium  below,  the  angle  at  4  below  being  133  1/3 
times  as  great  as  that  at  3.- 

A  ray  is  called  incident  before  it  enters  the  denser  medium, 
refracted  during  its  passage  and  emergent  after  it  has  passed. 

The  angle  formed  by  the  incident  ray  and  the  vertical  line 
A,  is  called  the  angle  of  incidence;  that  formed  by  the  re- 


Fig 


f racted  ray  and  the  same  line,  the  angle  of  refraction ;  and  that 
formed  by  the  emergent  ray  and  the  line  x,  the  angle  of 
emergence, 

A  ray,  in  making  a  passage  as  illustrated,  suffers  the  loss 
of  a  portion  by  reflection  at  the  first  surface,  and  it  is  a  law 


LIGHT  AND  REFRACTION.  J3 

of  optics  that  the  ang"le  of  reflection  always  equals  the  angle 
of  incidence,  hence  it  follows  that  the  reflected  portion  would 
pass  toward  F  forming  another  angle  with  the  line  A,  called 
the  angle  of  reflection. 

It  will  be  observed  that  the  angles  of  emergence  and  inci- 
dence are  of  equal  size;  therefore,  a  ray  starting  at  E,  would 
pursue  the  same  course,  and  R  would  be  the  emergent  ray, 
which  fact  gives  us  another  law,  viz. :  The  course  of  returning 
rays  is  always  upon  the  same  lines  on  which  they  enter. 

Fig.  4  illustrates  the  first  essentials  of  refraction.  Under- 
stand, the  word  means  "to  break."  Rays  passing  obliquely 
from  one  transparent  medium  to  another  of  different  density 
suffer  refraction.  But  they  must  not  approach  at  too  great  an 
angle  or  they  will  suffer  total  reflection.  Rays  on  the  lines 
"P^"  and  "p2"  would  pass  straight  through  the  glass  because 
they  strike  its  surfaces  perpendicularly.  As  the  density  of 
the  air  is  only  1.00  while  glass  is  1.50  (it  is  really  about  1.53, 
but  we  use  the  1.50  because  it  is  easier  to  make  the  calculations 
clear  to  the  student  and  the  principle  is  shown  as  well),  it 
follows  that  the  ray  will  pass  through  the  air  faster  than 
through  the  glass,  hence  to  get  the  comparative  rate  of  speed  in 
the  two  mediums  we  reverse  the  figures,  giving  air  the  1.50 
and  glass  the  1.00.  Then  one  inquires  what  becomes  of  the 
quantity  of  light,  indicated  by  the  figures  as  approaching  the 
glass,  greater  than  its  evident  capacity  to  receive.  It  is  re- 
flected as  perpendicularly  as  the  ray  strikes.  But  when  a  ray 
strikes  obliquely,  as  the  line  R,  the  reflected  portion  takes  a 
direction  as  oblique  as  the  ray  approached  and  on  the  other 
side  of  the  perpendicular.  The  amount  lost  by  reflection 
increases  as  the  angle  of  approach  increases  until  the  "limit 
angle"  is  reached,  which  is  about  fifty  degrees  from  the  per- 
pendicular, at  the  points  marked  40  and  140,  when  total  reflec- 
tion occurs.  The  ray  R,  called  the  incident  ray,  forms  an  angle, 
A,  with  the  perpendicular  and  it  is  called  the  angle  of  inci- 
dence. Imagine  there  is  nothing  shown  but  the  two  mediums, 
the  line  R,  the  perpendicular  and  the  line  A.     As  the  index 


J4  OPTICAL   TRUTHS. 

figure  of  glass  is  three  halves  while  that  of  air  is  only  two,  and 
as  the  speed  of  the  ray  in  the  air  is  the  greater,  we  know  the 
angle  must  be  also,  hence  we  take  the  measure  where  it  is 
easiest,  that  is,  where  it  measures  three  points;  (a  point  may 
be  a  millimeter,  an  eighth  of  an  inch,  or  any  other  unit  one 
chooses  for  a  calculation) ;  then  go  the  same  distance  below 
the  surface  of  the  glass,  B\  and  measure  two  points,  because 
that  represents  the  relative  speed  in  the  glass  and  the  relative 
size  of  the  angle  therein ;  then  draw  the  line  R  from  surface  to 
surface  of  the  glass  past  the  end  of  the  line  B^  this  is  the  re- 
fracted ray  and  the  angle  B^  is  the  angle  of  refraction.  Now 
imagine  the  line  P-  has  just  been  drawn  perpendicular  to  the 
lower  surface  of  the  glass  where  the  ray  strikes ;  we  know  the 
small  angle  is  in  the  glass  so  we  measure  B-,  two  points,  then 
go  as  far  on  the  other  side  of  the  surface  and  measure  three 
points  at  C,  then  continue  the  ray  from  where  we  left  it  at  the 
lower  surface,  toward  E.  This  is  the  emergent  ray  and  the 
angle  formed  by  it  with  the  perpendicular  is  the  angle  of 
emergence.  Note  that  a  ray,  whether  refracted  or  reflected, 
always  crosses  the  perpendicular;  that  the  angle  A  is  to  B' 
as  3  is  to  2,  and  the  angle  B'  is  to  C  as  2  is  to  3.  The  greater 
angle  is  always  in  the  rarer  medium,  therefore  if  we  know 
the  index  figures  of  the  two  mediums  we  can  find  where  a  ray 
will  go.  The  angle  of  reflection  is  always  equal  to  the  angle  of 
incidence.  The  ray  R  starts  toward  1,  is  broken  at  the  first 
surface  and  takes  direction  of  2,  is  broken  at  the  second  sur- 
face and  takes  final  course  to  E.  The  reasoji  a  ray  suffers 
refraction  is  that  as  it  approaches  obliquely  the  lower  side  of 
it  strikes  the  slow  speed  first  and  as  it  leaves  the  denser  me- 
dium the  lower  side  resumes  the  rapid  speed  first.  This  is  why 
in  entering  a  denser  medium  the  ray  is  broken  toward  the 
perpendicular  and  in  leaving  is  broken  from  the  perpendicu- 
lar. The  dot  in  the  middle  of  the  refracted  section  is  to  show 
that  if  it  were  the  luminous  point  from  which  rays  started  the 
one  directed  upward  and  that  directed  downward  would  strike 
the  respective  surfaces  at  the  same  angles,  hence  the  angle  of 


LIGHT  AND  REFRACTION.  J5 

incidence,  A,  and  the  angle  of  emergence,  C,  are  of  equal  size. 
But  this  is  not  always  true,  except  in  plane  surfaces. 

The  points  of  particular  interest  in  connection  with  this 
illustration  are: 

First.  An  oblique  ray,  passing  from  one  transparent 
medium  to  another  of  different  density  suffers  a  change  in  its 
path,  but  not  in  its  general  direction. 

Second.  The  denser  the  mediimi  the  slower  the  rate  of 
speed  of  the  ray. 

Third.  The  reflected  portion  passes  away  at  the  same 
angle  the  ray  approached. 

Fourth.    The  small  angle  is  always  in  the  denser  medium. 

Fifth.  There  is  a  duality  of  mediums,  a  duality  of  con- 
necting surfaces,  a  duality  of  perpendiculars  and  a  duality  of 
indices. 

Sixth.  There  is  a  positive  refraction  as  the  ray  enters 
the  denser  medium  and  a  negative  refraction  as  it  leaves; 
that  is,  the  ray  is  broken  toward  the  perpendicular  on  enter- 
ing and  from  it  on  leaving. 

Seventh.  There  is  a  double  duality  of  sections  of  the 
ray,  incident,  reflected,  refracted  and  emergent,  and  corre- 
sponding angles  formed  by  the  sections  and  the  perpendicu- 
lars. 

Eighth.  A  ray  suffers  reflection,  refraction,  dispersion 
and  absorption.  The  two  named  last  are  not  shown  in  the 
drawing. 

Ninth.  The  density  of  the  glass  compared  with  air  is  as 
1.50  is  to  1.00,  therefore,  the  angles  in  the  air  are  always  one- 
half  larger  than  in  the  glass,  and,  being  given  one  we  can 
always  find  the  other. 

Tenth.  The  comparative  angles  are  always  on  opposite 
sides  of  the  perpendicular,  as  they  are  on  opposite  sides  of 
the  connecting  surfaces  of  the  mediums. 

Eleventh.  The  amount  lost  by  reflection  gradually  in- 
creases until  the  limit-angle  is  reached,  when  the  ray  is  totally 
reflected. 


16 


OPTICAL   TRUTHS. 


Twelfth.  The  limit-angle,  where  total  reflection  occurs, 
symbolizes  one's  limit  of  endurance,  of  patience,  of  capacity, 
etc.,  metaphysically  and  physically. 


1 

) 

1    / 

/ 

^ 

l/f/aS\,l'SS'/i 

/ 

? 

iit^i.So 

/ 

1 

ISO    - 

^/       or 

CU^/.ffV 

Pig.    5 


In  order  to  make  indices  clearer,  Fig.  5  is  given  at  the 
risk  of  confusing  the  student.  Here  the  ray,  R,  starts  toward 
S  but  is  refracted  by  several  mediums  and  finally  passes  away 
on  the  line  0.    The  indices  given  are  all  in  comparison  with 


LIGHT  AND  REFRACTION. 

air,  so  that  in  the  refraction  which  occurs  as  the  ray  passes 
from  water  to  glass  and  from  glass  to  diamond,  we  must  find 
the  relation  they  bear  to  each  other,  which  is  easy  because 
all  we  have  to  do  is  find  the  ratio  the  figures  given  bear  to 
each  other;  thus  1.33  1/3=4/3  and  1.50=3/2;  then  multiplying 
the  denominators  to  get  the  common  denominator,  we  get  6; 
as  4/3=8/6  and  3/2=9/6,  the  relation  between  water  and  glass 
is  as  8  to  9,  and  if  8  is  100  per  cent,  9  is  1.12  1/2  per  cent, 
hence  the  last  figure  is  the  index  of  glass  when  compared  with 
water.  The  figures  for  glass  being  1.50=5/2  and  for  diamond 
2.50=^5/2,  there  is  already  a  common  denominator,  and  they 
bear  the  relation  of  3  to  5;  if  3  is  100  per  cent,  5  is  1.66  2/3 
per  cent,  and  is  the  index  of  diamond  compared  with  glass. 
The  lengths  of  lines  in  the  cut  bear  out  the  respective  indices 
in  their  proportion  to  each  other.  The  line  4  is  to  3  as  1.33  1/3 
is  to  1.00;  the  line  9  is  to  8  as  1.50  is  to  1.33  1/3;  the  line  5  is 
to  3  as  2.50  is  to  1.50;  the  line  1  is  to  2  1/2  as  1.00  is  to  2.50. 
The  vertical  lines  1,  2,  3,  4  are  the  perpendiculars  to  the 
surfaces  where  refractions  occur. 


Fig- 


Fig.  6  shows  how  to  find  the  index  of  a  medium  if  both 
the  incident  and  refracted  sections  and  the  index  of  the  rare 
medium  are  given.    Knowing  that  the  index  of  air  i«  1.00 


t8 


OPTICAL   TRUTHS. 


all  that  need  be  done  is  to  erect  the  perpendicular,  P,  measure 
the  angle  at  1  and  go  as  far  outside  the  globe,  along  the  line 
P,  as  the  first  angle  is  inside,  measure  the  angle  at  2,  which, 
being  2.22  times  as  great  as  1,  proves  the  index  of  such  a 
medium  would  be  2.22. 

A  globe  of  glass,  with  1.50  index  focuses  beyond  itself,  as 
is  shown  in  Fig.  7. 

P' 


fi     \  .s 


LIGHT  AND  REFRACTION.  J9 

If  the  globe  were  a  diamond,  the  focus  would  be  as  shown 
by  the  dotted  lines,  Fig.  7,  the  angle  of  incidence  2  1/2  and 
angle  of  refraction  1.  I  do  not  like  to  make  one  drawing  tell 
too  many  things,  but  it  is  not  desired  to  give  too  much  promi- 
nence to  practically  useless  features,  which,  nevertheless,  are 
valuable  theoretically. 

Fig.  8  shows  what  happens  to  a  ray  in  passing  a  prism. 
In  Figs.  4  and  5,  the  surfaces  were  parallel,  so  that  had  rays 
approached  perpendicular  to  the  first  surface,  they  would  have 
also  been  perpendicular  to  the  second  and  would  have  passed 
through  without  refraction.  By  this  figure  it  will  be  seen  no 
ray  can  pass  without  refraction,  for  if  it  came  to  the  first  sur- 
face perpendicularly  it  would  be  refracted  by  the  second 
surface,  because  it  is  not  parallel  with  the  first.  A  ray  start- 
ing from  A  toward  C  would  be  refracted  by  the  first  surface 
toward  2,  and  by  the  second  surface  toward  B;  and  a  ray 
starting  from  B  toward  0  would  first  be  changed  to  the  direc- 
tion X,  then  toward  A.  Thus  an  eye  at  A  would  see  at  C 
an  object  really  situated  at  B,  and  an  eye  at  B  would  see  at  0 
an  object  really  located  at  A.  Rays  are  always  refracted 
toward  the  base  of  a  prism  and  objects  seen  through  a  prism 
always  appear  nearer  the  apex. 

As  there  is  no  transparent  material  having  the  index  indi- 
cated by  Fig.  6  and  as  glass  would  only  focus  as  shown  by 
Fig.  7,  if  we  wanted  a  glass  apparatus  that  would  focus  at 
its  posterior  pole  we  would  have  to  make  the  anterior  curva- 
ture from  the  Center  C,  Fig.  9,  instead  of  from  the  center,  N, 
thus  making  up  in  angle  of  incidence  what  is  lacking  in  dens- 
ity. The  refraction  of  R^  having  been  measured,  and  the  sur- 
face being  spherical,  we  know  where  R'  would  go  without 
measuring. 

These  apparent  objects  are  called  virtual  objects  because 
we  do  not  see  the  real  thing.  As  a  matter  of  strict  fact  all 
who  wear  glasses  only  see  virtual  object-,  for  convex  lenses 
magnify  and  concave  ones  minify.  This  is  compensated  for, 
however,  by  the  facts  that  those  who  need  convex  lenses  have 


20 


OPTICAL   TRUTHS. 


eyes  that  do  not  magnify  as  much  as  normal  ones  and  those 
who  need  concave  lenses  have  eyes  that  magnify  more  than 
normal,  thus  nature  takes  care  of  her  children.  In  figure  8 
the  lines  P^  and  P-  are  perpendicular  to  the  surfaces,  and  the 
lines  N  N  and  K  K  show  where  the  angles  were  measured. 

f 


Fig.    9 


Prisms  in  multitudinous  quantities  form  all  lenses  of  every 
description.  If  placed  bases  together  as  shown  in  Fig.  10, 
there  will  be  positive  effects,  hence  such  lenses  are  known 
as  +•  I^  the  prisms  are  reversed  as  shown  in  Fig.  11,  the 
effects  are  negative,  hence  lenses  having  this  general  form 
are  known  as  — . 


Observe  in  both  Figs.  10  and  11  the  central  lines  pass 
through  without  refraction;  this  is  because  the  two  surfaces 
are  in  such  relative  position  that  they  are  parallel  at  these 
lines  and  the  rays,  being  perpendicular,  pass  without  refrac- 
tion; hence  the  lines  are  called  axes  and  the  rays  are  axial 
rays. 

Note  in  Fig.  10  that  while  parallel  rays  meet  on  the  axis 


LIGHT  AND  REFRACTION. 


2i 


after  passing  the  prisms,  they  do  not  meet  at  a  point  common 
to  all.  In  order  to  utilize  the  principles  of  refraction  for 
optical  purposes  it  is  necessary  to  grind  curved  surfaces  so 
there  will  be  the  effects  of  a  multitude  of  prisms  of  different 
angles  in  order  that  there  may  be  at  least  approximately  one 


Fig-.   11 

focal  point  for  all  rays  that  come  parallel  with  the  axis  or 
divergent  from  the  same  given  points  on  the  axis.  If  the  rays 
approach  parallel  with  the  axis  they  meet  at  the  nearest  possi- 
ble point  on  the  axis  after  passing  the  lens;  this  is  called  the 
principal  focus. 

P 


n 

/ 

/ 

^^^TT^-^-^-^^^^:^^ 

- 

^ "       '^ 

l< 

\a 

V            \ 

Fig.    12 


In  Fig.  12,  R  and  R  approach  parallel  to  the  axis  but  at 
different  distances  from  it,  but  the  angles  A  and  B  bear  the 


22 


OPTICAL   TRUTHS. 


same  relation  to  each  other  in  both  instances  and  the  result  is 
that  the  rays  focus  at  the  same  point  on  the  axis.  The  fact 
that  the  curvature  would,  if  continued,  form  a  perfect  sphere, 
caused  the  name  spherical  to  be  given  such  lenses.  They  may 
be  either  convex  or  concave,  and  each  class  is  subject  to  three 
forms  of  construction  as  shown  in  Fig-.  13. 


Fig.    13 


Fig.  13  illustrates  the  positive  (4-)  and  negative  ( — ) 
structure  of  spherical  lenses,  one  set  is  cut  from  the  globes 
and  one  set  so  that  globes  would  fit  in  them.  Particular  atten- 
tion is  directed  to  understanding  the  little  essentials,  which, 
I  have  found  in  school  work,  are  often  neglected.  Fig.  14 
shows  edge  views  of  lenses  corresponding  to  Fig.  13. 


Fig-.   14 


These  are  the  popular  forms,  but  there  are  many  others 
embodying  the  same  principles,  such  as  the  lenticulars,  as  they 
are  called,  for  which  a  piece  of  plane  glass  is  used  to  get  the 
size,  and  in  the  center  a  small  space  is  ground  to  desired  curva- 
tures in  —  and  for  -|-  a  small  piece  is  cemented  on.    Fig.  15 


LIGHT  AND  REFRACTION.  23 

shows  first  the  front,  then  the  edge  views  of  such  lenses. 
Then  there  are  lenses  ground  like  Fig.  15  on  -(-  lenses  1,  2,  3, 
Fig.  14,  for  the  purpose  of  making  strong  lenses  without  the 
thick  edges  of  4,  5  and  6,  Fig.  14.  Then  there  are  alleged 
toric  lenses  and  real  torics  and  sphero-torics.  The  American 
standard  periscopic  or  meniscus  lenses  are  ground  with  fixed 
amount  of  concavity  on  one  side  and  with  enough  convexity 
on  the  other  to  give  the  desired  focal  power.  During  the  past 
few  years  opticians  who  are  not  content  with  reasonable  prices 
for  ordinary  lenses,  foisted  upon  gullible  people,  including 
many  oculists,  what  they  call  a  toric  lens,  but  which  is  noth- 
ing more  or  less  than  a  deep  concavity  on  one  side  of  a  men- 
iscus.    They  are  not  only  of  no  benefit,  but  are  really  harm- 


ful, because  they  intensify  spherical  and  chromatic  aberra- 
tion in  the  stronger  numbers,  and  oculists  who  endorse  them 
advertise  their  culpable  ignorance  of  optical  principles  and 
physical  laws  generally.  Before  explaining  the  toric  lens  I 
must  give  some  preliminary  facts: 

Chemically  glass  belongs  to  the  class  called  salts.  Com- 
mon glass  is  made  by  melting  together  silica  (sand),  calciimi 
carbonate  (limestone),  and  sodium  carbonate  (soda).  If 
potassium  be  substituted  for  sodium,  and  lead  for  calcium, 
the  quality  is  finer;  in  other  words,  the  finer  the  material 
used  the  better  the  product.  Flint  is  clearer  than  crown  glass 
because  there  is  lead  in  its  composition,  but  it  is  softer,  which 
gives  it  a  peculiar  quality  to  be  described. 

It  is  well  known  that  natural  light  is  composed  by  a  com- 


24  OPTICAL   TRUTHS. 

bination  of  all  the  spectral  colors.  The  passage  of  a  ray 
through  any  medium  which  reduces  its  original  speed  causes 
a  derangement  of  its  components,  the  medium  absorbs  a  por- 
tion, while  it  also  makes  an  attempt  to  disperse  it  into  its  ele- 
mentary colors;  so,  any  ray,  in  passing  from  one  transparent 
medium  to  another  of  different  density,  suffers  from  reflection, 
dispersion  and  absorption;  and,  if  it  passes  obliquely,  it  also 
suffers  refraction. 

Were  it  not  for  reflection  we  could  not  see  objects  which 
are  not  luminous;  and,  w^ere  it  not  for  dispersion  and  absorp- 
tion the  power  of  the  reflected  light  would  be  so  great  as  to 
be  painful  to  the  nerves  of  vision. 


Red/ 

Qia.itoe 


Fig-.    16 


Fig.  16  illustrates  the  dispersive  power  of  glass,  with  the 
ray  passing  from  A  toward  R,  at  such  an  angle  of  incidence 
that  the  greatest  possible  effect  from  the  prism,  C,  is  shown. 

Flint  glass,  with  a  refractive  power  about  equal  to,  has 
twice  as  much  dispersive  power  as  the  crown  glass  from  which 
spectacle  lenses  are  made,  so  that  a  prism  of  half  as  great 
angle  as  the  cut  shows,  would,  if  made  from  flint  glass,  exhibit 
as  much  dispersion.  It  was  the  discovery  of  this  which  en- 
abled the  makers  of  the  finer  grades  of  optical  and  mathe- 
matical instruments  to  attain  their  present  approximate  to 
perfection.  Previously  two  factors  interfered  with  the  suc- 
cessful use  of  lenses  with  more  than  about  twenty-five  diam- 
eters magnifjdng  power.  These  were  chromatic  and  spherical 
aberration.  No  single  lens  will  focus  absolutely,  because 
while  the  density  is  constant  the  angles  at  which  the  rays 
strike  the  surfaces  increase  steadily,  as  they  are  farther  from 


LIGHT  AND  REFRACTION, 


25 


the  axis,  so  that  the  effects  illustrated  by  Fig.  16  are  exhibited 
by  the  lens  as  shown  in  Fig.  17,  the  rays  1  and  1  show  no 
aberration,  while  rays  2  and  2  illustrate,  first,  that  the  edge 
rays  meet  on  the  axis  just  a  little  sooner  than  the  more  central 
ones,  thus,  in  high  power  lenses  causing  indistinct  images  to 


A)(ff 


Fig-.    17 

be  formed;  second,  the  dispersion  would  also  cause  color  dis- 
turbances. The  discovery  of  the  difference  between  crown 
and  flint  glass  enabled  the  manufacturers  to  overcome  both 
of  these  factors  and  thus  utilize  the  whole  field  of  the  lens. 
Formerly  it  was  necessary  to  rough-grind  the  marginal  field 
to  even  partly  overcome  the  difficulties. 

3 


Fig.  18  shows  the  dispersion  of  the  ray  from  R  in  the 
crown  glass,  C,  and  the  contrary  effect  in  the  flint  glass,  F, 
which  reunites  the  parts,  and  the  emergent  ray  becomes  white 
again.  The  flint  glass,  3,  being  half  as  strong  in  refractive 
power  as  the  crown,  6,  and  of  the  same  dispersive  power,  the 


26 


OPTICAL   TRUTHS. 


result  is  a  refractive  power  of  3  in  the  combination,  without 
any  dispersion.  It  is  upon  this  principle  that  achromatic  and 
aplanatic  lenses  are  made.  The  first  means  the  chromatic 
aberration  is  corrected,  and  the  second  is  a  lens  in  which  all 
faults  are  overcome. 


t'lg-.    19 


Fig.  19  shows  how  an  aplanatic  lens  is  constructed;  the 
center  piece  being  of  the  formula  C,  while  the  two  outer  pieces 
are  of  the  formula  F,  each  having  one-fourth  of  the  refractive 
power  of  the  inner  piece.  It  would  work  just  as  well  with 
reference  to  the  dispersion  if  the  two  outer  pieces  were  one, 
and  half  as  strong  as  the  center  piece,  but  by  making  two 
pieces  and  putting  one  on  either  side  another  defect  was  over- 
come, namely,  spherical  aberration,  caused  by  the  edge  rays 
focusing  sooner  than  the  ones  which  pass  through  the  lens 
near  the  center.  Remember  there  are  two  laws  which  govern 
the  amount  of  refraction  by  lenses:  that  of  density  and  that 
of  angle  at  which  rays  strike  the  surfaces. 

Now  we  may  see,  with  the  aid  of  Figs.  20  and  21,  the 
objects  of  a  toric  lens.  First,  understand  that  in  architecture 
a  tore  is  an  ornament  placed  on  pillars ;  it  would  be  well  illus- 
trated by  putting  a  bicycle  tire  around  a  large  pillai',  show- 
ing its  long  curve  around  the  pillar  and  its  short  curve  around 
itself;  hence  a  toric  lens  is  so  named  because  it  has  not  a 
spherical  curvature  but  is  curved  in  all  meridians.  It  also 
illustrates  aptly  a  natural  law  that  in  non-spherical  surfaces 
the  two  principal  meridians  are  always  at  right  angles  to  each 


LIGHT  AND  REFRACTION. 


27 


other,  and  when  they  are  taken  care  of  the  other  meridians  are 
also  provided  for  without  further  attention.  Yet  there  are 
alleged  scientific  oculists  and  opticians  who  prescribe  and 
make  cross-cylinder  lenses  with  axes  not  at  right  angles  to 
each  other,  and  when  criticized  declare,  "Well,  I  get  better 
results  from  them  anyhow,"  thus  clinching  the  proof  they 
do  not  know  their  business. 


H 


^■f. 


■P.St, 


\l 


Fig.   20 


Pig-.   21 


Fig.  20  shows  how  a  sphero-toric  lens  is  made  where  the 
two  principal  meridians  are  +  11.  and  +8.  respectively.  Add 
the  figures  above  the  axis  for  the  maximum  meridian,  and 
those  below  the  axis  for  the  minimum.  When  the  student 
is  familiar  with  prescription  writing,  as  detailed  later, 
this  will  be  more  comprehensive.  Fig.  21  shows  how  a 
sphero-toric  can  be  and  often  is  made,  which  aborts  the 
purpose  for  which  nature  gave  the  principle.  By  first  grind- 
ing — 5.  on  one  side  there  was  caused  a  necessity  for  -\~  16. 
curvature  in  the  meridian  of  maximum  need  to  get  the  -f  11. 
required,  and  for  -|-  13.  in  the  meridian  of  minimum  need  to 
get  the  +  8.  when  the  facts  illustrated  by  Fig.  19  prove  that 
the  whole  object  in  making  lenses  as  flat  as  possible  to  get 
the  desired  effects  is  because  the  nearer  flat  they  are  the  nearer 
perfect  they  are.  Nature  made  the  crystalline  lens  of  the  eye 
on  the  same  principles  as  the  aplanatic  lens  shown  here,  and,  1 
believe,  for  the  same  reasons,  hence  I  assert  that  the  rod-and,. 


28 


OPTICAL   TRUTHS. 


cone  theory  of  color-blindness  is  wrong-,  that  most  cases  of 
color-blindness  are  color  ignorance  and  the  remainder  are 
due  to  homogenity  of  the  lens  structure. 


Fig-.   22 

Fig.  22  shows  how  a  plano-convex  lens  focuses  parallel 
rays  practically  at  the  opposite  side  of  the  circle  of  which 
the  lens  is  a  segment.  This  would  be  true  of  any  size  circle 
or  globe  of  glass  and  from  this  fact  the  system  of  numbering 
lenses  was  evolved.  The  word  "meter"  means  "measure," 
hence  a  circle  one  meter  in  diameter  was  chosen  as  the  stand- 
ard and  all  lenses  are  numbered  inversely  as  their  focal  power 
in  inches  equals  meters  or  parts  of  meters.  The  numbers 
apply  to  —  lenses  as  they  neutralize  their  equivalents  in  -f-, 
for  the  —  are  only  positive  by  reflection,  as  shown  in  Fig.  26. 
Thus  having  a  standard. 

No.  1.00  curvature  equals  1  meter  focal  power. 

No.  2.00  curvature  equals  1-2  meter  focal  power. 

No.  3.00  curvature  equals  1-3  meter  focal  power. 

No.  4.00  curvature  equals  1-4  meter  focal  power. 

No.  5.00  curvature  equals  1-5  meter  focal  power. 

No.  6.00  curvature  equals  1-6  meter  focal  power. 


LIGHT  AND  REFRACTION.  29 

No.  7.00  curvature  equals  1-7  meter  focal  power. 

No.  8.00  curvature  equals  1-8  meter  focal  power. 

No.  9.00  curvature  equals  1-9  meter  focal  power. 

No.  10.00  curvature  equals  1-10  meter  focal  power. 

The  metric  system  is  a  decimal  system  of  weights  and 
measures  used  almost  universally.  Its  unit  is  1  meter,  the 
ten-millionth  part  of  one-quarter  of  a  meridian  circle  of  the 
earth. 

1,000  meters  =  1  kilometer. 

100  meters  =  1  hectometer. 

10  meters  =  1  decameter. 

1  meter  =  1  meter. 

.1  meter  ^  1  decimeter. 

.01  meter  =  1  centimeter. 

.001  meter  =  1  millimeter. 

As  many  are  not  familiar  with  the  metric  system,  except 
8is  we  use  it  in  money,  and  few  know  it  is  subdivided  metric- 
ally, I  would  explain  that  a  meter  is  39.368  inches,  or,  for 
mental  calculations,  call  it  40  inches.    Then 

No.  1.00  curvature  equals  40  inches  focus. 

No.  2.00  curvature  equals  20  inches  focus. 

No.  3.00  curvature  equals  13  inches  focus. 

No.  4.00  curvature  equals  10  inches  focus. 

No.  5.00  curvature  equals  8  inches  focus. 
and  so  on.  Having  the  number,  to  find  the  focus,  divide  it  into 
40;  or,  having  the  focus,  to  find  the  number,  divide  it  into 
40.  Thus,  15  inches  focus  divided  into  40  goes  2  2/3  times. 
Express  it  decimally  as  2.66,  leaving  out  the  small  fraction. 
Then  remember  the  standard  is  not  quite  40  inches,  but  is 
exactly  1.00  and  that  1.00  cut  into  eighths  would  be  .12^4 
.25,  .371/2,  .50,  .621/2,  .75,  .871/2,  1.00.  We  arbitrarily  call 
the  2.66  a  2.62  because  lenses  are  ground  only  to  eighths.  A 
No.  .50  would  go  into  40  just  80  times,  hence  the  focus  of  a 
-f-  .50  lens  would  be  twice  as  far  as  -f  1.00  and  that  of  a 
-|-  2.00  would  be  half  as  far  as  plus  1.00,  or  20  inches.  Thus 
having  any  figure  in  on«  column,  to  find  its  equivalent  in 


30 


OPTICAL  TRUTHS. 


the  other,  divide  it  into  40.     Or,  to  be  more  exact,  divide  it 
into  39,368. 

The  rule  of  calculation  of  indices,  curvatures  and  focuses 
is:  Having  the  focus  desired  and  the  index  of  refraction,  to 
find  the  radius  of  curvature  necessary,  multiply  the  focus  by 
the  index  less  1.00.  Thus  the  focus  of  a  No.  1.00  lens  is  39.368 
inches;  the  index  of  refraction  of  glass  is  1.53.  The  .53  being 
in  excess  of  the  standard,  air,  is  w^hat  we  use.  39.368  X  -53 
equals  20.86504  inches  or  the  radius  of  curvature  upon  which 
the  lens  must  be  ground.  Thus  we  find  the  focus  is  a  little 
shorter  than  the  diameter  of  the  circle,  Fig.  22.  Or,  being 
given  the  radius  and  index,  to  find  the  focus,  divide  the  radius 
by  the  index  less  1.00.  Or,  being  given  the  focus  and  radius, 
to  find  the  index,  divide  the  radius  by  the  focus  and  add  1.00. 
If  a  biconvex  is  wanted  the  two  radii  must  be  twice  as  great 
as  for  a  plano-convex;  or  if  a  meniscus  is  wanted  the  radius 
must  be  shortened ;  thus  if  -j-  10  is  to  be  made  meniscus  form, 
with  —  1.25  on  one  side,  the  radius  of  the  +  curvature  would 
have  to  be  shortened  to  make  +  11.25  effect,  so  the  —  1.25 
would  be  neutralized  and  leave  the  full  +  .10. 


Fig-.    23 


LIGHT  AND  REFRACTION. 


3J 


Fig.  23  shows  the  principal  points  and  planes  of  a  bi-con- 
vex  lens.  The  points  are  all  on  the  axis  and  the  planes  are 
the  vertical  lines  crossing  the  axis  at  the  points.  A  and  A 
locate  the  principal  points  and  planes:  B  and  B,  the  principal 
focal  points  and  planes ;  C  and  C,  the  optical  nodal  points  and 
planes;  D,  the  optical  center  and  its  plane.  N  and  N  are  the 
true  nodal  points,  or  centers  of  curvature  of  the  respective 
surfaces,  from  which  the  perpendiculars  are  drawn.  The 
lines  R  and  R'  show  how  rays  approaching  parallel  to  the  axis 
will  be  focused  at  the  principal  focal  points.    The  line  X  to 


Fig.   24 

X^  shows  how  the  secondary  axial  rays  suffer  refraction,  and 
locate  not  only  the  optical  nodal  points,  but  the  optical  cen- 
ter; X  passing  in  the  direction  0  is  refracted,  crosses  the  prin- 
cipal axis  at  the  optical  center  and  passes  away  to  X'  as  if 
it  came  from  0'.  The  optical  nodal  points  are  where  the 
rays  X  and  X^  would  cross  the  axis  if  they  did  not  suffer  re- 
fraction. This  is  of  no  great  importance,  but  is  of  passing 
interest. 

Conjugate  foci  are  those  points  on  either  side  of  a  +  lens 
at  which  are  situated  an  object  and  its  image.  If  an  object  be 
placed  at  the  point  on  the  left.  Fig.  24,  and  the  ray  of  direc- 
tion drawn  to  the  lens  L  through  the  principal  focal  plane  P, 
then  a  guide  line  be  drawn  from  the  point  where  the  ray 
crosses  the  focal  plane  through  the  optical  center  of  the  lens, 


32 


OPTICAL   TRUTHS. 


then  the  ray  continued  parallel  to  the  guide  line,  the  point 
where  it  meets  the  axis  will  be  the  location  of  the  image.  It 
makes  no  difference  where  the  ray  of  direction  is  made  so  it 
hits  the  lens.  The  reason  this  works  exactly  is  that  any  ray 
starting  divergent  from  the  axis  at  the  point  where  the  line 
P  crosses,  will  be  refracted  and  pass  away  parallel  to  the  axis, 
and  any  ray  starting  from  any  point  on  that  plane,  divergent 
from  its  secondary  axis,  represented  by  the  guide-line,  will 
be  refracted  and  pass  away  parallel  to  that  axis. 

A 


I 


1     ^ 


Fig.   25 


Fig.  25  shows  how  the  law  of  conjugate  foci  works  in 
producing  the  image.  The  direct  rays  from  1  to  1  and  from 
3  to  3  are  secondary  axes  and  the  divergent  rays  from  each 
converge  to  the  corresponding  jfigures  on  the  other  side  for 
the  same  reason  that  those  from  the  principal  axis  2  converge 
to  it  again  at  2  on  the  other  side.  The  fact  that  the  secondary 
rays  cross  the  principal  axis  at  the  optical  center  accounts  for 
the  reversal  of  the  image.  There  is  a  multitude  of  secondary 
axes,  but  the  extreme  ones  given  show  how  they  all  act.  If 
an  object  be  placed  at  twice  the  principal  focal  distance  from 
any  lens  the  image  will  be  formed  at  the  same  distance  on 
the  other  side;  if  the  object  be  at  three  times  the  focal  dis- 
tance the  image  will  be  nearer  and  half  size;  if  object  is  at 
four,  five,  six,  etc.,  times  the  principal  focal  distance,  the  pic- 
ture will  be  nearer  and  proportionately  smaller  until  the  object 
is  at  infinity,  when  the  image  will  be  at  the  principal  focal 


LIGHT   AND  REFRACTION.  33 

point  on  the  other  side.  Infinity  is  the  distance  sufficient  so 
that  any  greater  one  makes  no  perceptible  change  in  the  loca- 
tion of  the  image;  fifteen  or  twenty  feet  fairly  express  it.  If 
the  object  be  placed  nearer  than  twice  the  focal  distance  the 
image  will  be  farther  away  and  enlarged.  If  the  object  be 
placed  nearer  the  lens  than  the  principal  focus,  the  rays  will 
be  divergent  after  passing  it  and  there  will  be  no  image.  The 
point  upon  the  principal  axis  where  the  object  is  placed  is  the 
first  conjugate  focal  point,  and  the  corresponding  point  on 
the  other  side  of  the  lens,  where  the  image  is  formed,  is  the 
second  conjugate  focal  point,  and  the  distances  between  each 
of  those  points  and  the  lens  are,  respectively,  the  first  and 
second  conjugate  focal  distances.  A  rule  to  locate  where 
images  will  be  formed  is  to  multiply  the  first  conjugate  focal 
distance  by  the  focal  length  of  the  lens  and  divide  the  product 
by  the  difference  between  the  first  two  figures ;  the  result  will 
be  the  second  conjugate  focal  distance,  which,  in  -|-  lenses  is 
always  on  the  opposite  side  of  the  lens.  The  word  "conju- 
gate" means  "yoked  together,"  and  it  is  applied  to  the  points 
described  because  they  are  movable,  the  position  of  the  second 
being  always  dependent  upon  the  first.  A  better  rule  is  to 
express  the  first  conjugate  focal  distance  in  diopers,  deduct  it 
from  the  power  of  the  lens  and  convert  the  remainder  into 
inches.  Having  both  conjugate  foci  to  find  the  power  of  the 
lens,  express  both  in  diopters  and  add  them. 

Fig.  26  shows  how  a  —  lens  forms  images  by  reflection. 
Rays  1  and  3  are  reflected  as  2  and  4,  while  the  principal  axial 
ray  is  reflected  back  on  its  own  line;  5  is  reflected  as  6,  and 
others,  not  shown  in  the  cut,  fall  in  between,  forming  the 
image  reversed.  Other  writers  have  misled  readers  by  show- 
ing with  Fig.  25  that  +  lenses  form  "real  images  reversed," 
and  by  Fig  27  that  —  lenses  form  "virtual  images  erect," 
which  is  not  true,  as  the  student  may  determine  readily  if  he 
will  take  two  lenses,  one  -\-  and  one  — ,  look  through  each  at 
some  object,  preferably  a  light  at  some  distance,  when  he  will 
see  a  "virtual"  erect  object  with  either,  enlarged  with  the 


34 


OPTICAL   TRUTHS. 


Pig.   26 


+  and  reduced  with  the  — .  Then  by  holding  a  piece  of 
blank  paper  with  the  -f-  lens  between  it  and  the  light  he  will 
find  a  "real"  image  inverted;  next  hold  the  paper  between 
the  light  and  the  —  lens  but  a  trifle  lower  and  tilt  the  lens 
so  it  will  reflect  on  the  paper  and  he  will  see  another  "real" 
image,  inverted,  too. 


Fig.   27 

If  the  effect  of  the  combinations  of  spheres,  placed  some 
distance  apart,  is  wanted,  make  a  drawing  like  Fig.  28.  L' 
and  L-  represent  the  lenses ;  P^  and  P-  represent  the  respective 


LIGHT  AND  REFRACTION. 


35 


focal  planes.  In  this  cut  the  lenses  are  each  +  3.25  and  1/16 
inch  represents  an  inch,  thus  the  lenses  are  6  inches  apart. 
The  incident  ray  A  approaches  L^  divergent  and  crosses  its 
plane  PS  in  its  course.  For  the  reasons  shown  in  Fig.  24,  the 
ray  would  be  refracted  by  L^  and  pass  toward  L-  parallel 
to  the  gnide  line  X  drawn  from  the  principal  focal  plane 
through  the  center  of  L^;  then  projecting  it  backward  on  its 
new  course  until  it  strikes  the  plane  PS  drawing  a  guide  line, 
X=,  from  there  through  the  center  of  the  second  lens,  and  con- 


P^     iL 


^fc 


P1&.    28 

tinning  the  ray  parallel  to  it  until  it  strikes  the  axis,  there  will 
be  the  conjugate  focus  with  the  point  from  which  the  inci- 
dent ray,  A,  started. 

If  the  ray  A  approached  parallel  with  the  axis  and  the 
power  of  the  lenses  is  known  its  course  from  the  first  to  the 
second  lens  may  be  drawn  arbitrarily,  then  proceed  as  above. 

Fig.  29  shows  another  class  of  lenses,  in  which  the  prisms 
are  arranged  on  either  side  of  a  line,  instead  of  around  a 
point;  bases  are  at  the  line  for  -j-  and  apices  at  the  line  for 
— .  These  are  called  cylindrical  lenses,  because,  if  the  curva- 
tures of  the  -f  were  continued  they  would  form  cylinders. 
Rays  passing  through  on  the  lines  marked  "axis"  suffer  no 
refraction,  but  all  others  do.  A  -f-  cylinder  refracts  all  rays 
on  either  side  of  its  axis  toward  the  line,  thus  what  is  termed 
the  "focus"  of  a  cylinder  is  merely  causing  a  lot  of  rays  to 
form  a  wedge,  the  thin  part  being  on  the  axis  and  the  wide 
part  being  equal  to  the  extreme  width  of  the  lens.  A  — 
cylinder  refract.?  rays  from  its  axis,  hence  can  only  form  a 


36  OPTICAL  TRUTHS. 

wedge  of  light  by  reflection.  Cylinders  are  numbered  same 
as  spheres  because  in  the  meridian  of  greatest  power  of  each 
they  are  equal  to  spheres  of  the  same  curvature.  They  are 
made  only  in  the  forms  plano-convex  and  plano-concave  be- 
cause of  the  frequent  necessity  of  combining  them  with 
sphericals  to  make  what  are  called  sphero-cylinders,  or  com- 
pound lenses.  In  toric  lenses  the  sphere  and  cylinder  are 
ground  on  the  same  side  of  the  lenses.  The  points  to  be  noted 
particularly  with  reference  to  cylinders  are  that  there  are 
two  principal  meridians,  at  right  angles  to  each  other;  one  is 
the  axis,  the  other  the  meridian  of  maximum  power ;  therefore 
in  combining  them  with  spheres,  they  impart  that  quality  to 
the  combination,  the  sphere  furnishing  all  the  power  on  the 
axis   and   both   supplying  power   on  the   opposite   meridian, 


Fig.    29 

where,  if  both  have  the  same  sign  they  must  be  added,  and  if  of 
opposite  signs  they  must  be  subtracted;  if  of  opposite  signs 
and  of  the  same  power  they  neutralize  each  other  and  the  com- 
bination can  be  duplicated  with  a  simple  cylinder.  See  next 
chapter  for  this  work. 

Hold  a  prism,  base  down,  a  few  inches  from  the  eye,  and 
look  through  it  at  some  fixed  object ;  there  will  be  an  apparent 
displacement  of  the  object  toward  the  apex  of  the  prism, 
because  the  rays  are  broken  toward  the  base.  Move  the  prism 
from  right  to  left  and  reverse,  when  there  will  be  no  move- 
ment of  the  object.  Rotate  the  prism  and  the  object  will 
move  in  a  circle  with  apex  of  prism. 

Hold  a  -f  sphere  in  the  same  manner  and  there  will  be 
no  displacement,    because    there    are   a  great  many  prisms 


LIGHT  AND  REFRACTION.  37 

arranged  around  a  center.  The  object  may  appear  enlarged 
more  or  less,  governed  by  the  distances.  Move  lens  to  and 
fro  and  the  object  will  be  displaced  in  the  opposite  direction. 
Rotate  the  lens  and  the  object  will  remain  stationary. 

A  —  sphere  treated  in  like  manner  causes  the  object  to 
move  with  it,  otherwise  it  will  be  just  like  the  +,  except  that 
objects  seen  through  it  will  appear  reduced. 

A  -f  cylinder,  held  axis  90  and  moved  up  and  down  will 
not  displace  the  object;  but  when  moved  to  and  fro  will 
displace  the  object  in  the  opposite  direction.  Rotate  it  and 
the  vertical  meridian  will  go  against  the  movement,  while 
the  horizontal  meridian  will  go  with  it.  This  is  because  the 
apices  of  the  cylinders  are  down  on  one  side  and  up  on  the 
other. 

A  —  cylinder  axis  90,  will  cause  no  motion  of  object 
when  moved  up  and  down,  but  moved  sidewise  will  cause  a 
movement  with  the  lens.  Rotated  it  will  cause  the  vertical 
meridian  of  the  object  to  move  with  its  motion  while  the 
horizontal  will  reverse,  for  the  same  reasons  given  for  the  -|- 
cylinders. 

The  prisms  being  reversed  the  effects  are  also,  as  a  mat- 
ter of  course. 

Knowing  the  peculiarities  of  each  lens  in  its  simplest  form 
it  is  easy  to  find  how  many  departments  there  are  to  a  lens. 
For  example,  if  a  lens  be  shaken  and  objects  move  in  every 
direction  it  is  proof  there  is  a  sphere;  if,  in  addition  there  is 
greater  movement  in  one  principal  meridian  than  in  the  other 
it  tells  there  is  a  cylinder,  or  if  rotating  distorts  objects  it  tells 
of  a  cylinder;  while  if  rotating  moves  the  object  in  a  circle, 
but  does  not  distort  it,  a  prism  is  present.  If  all  the  effects 
are  there,  all  the  causes  are  also. 

This  exhibition  of  law  affords  us  a  lesson  in  practice. 
We  must  know  what  symptoms,  objective  or  subjective,  mean, 
then  if  we  find  several  symptoms  we  know  there  are  several 
causes.  Our  symptoms  are  not  like  those  of  the  old  schools, 
a  sort  of  guide  to  diagnosis  only,  but  to  complete  analysis. 


PRESCRIPTION  WRITING. 

Analysis  and  Neutralization  of  Lenses  Prove  a  Simple  Natural 

Law. 

A  +  lens  which  brings  parallel  rays  to  a  focus  at  one 
meter  (39.368  inches)  beyond  it  is  taken  as  the  standard  of 
measure  and  is  numbered  1.00.  When  the  power  is  increased 
the  focus  is  shortened;  thus  -[-  2.00  will  focus  at  1/2  the  dis- 
tance +  1.00  does;  +  3.00  at  1/3;  -f  4.00  at  1/4,  etc.  For 
mental  calculations,  remember  -j-  1.00  equals  40  inches  focus. 

As  -j-  1.00  is  the  number,  and  40  inches  the  focal  length, 
of  the  unit  of  measurement,  if  we  have  the  number  of  a  lens 
and  want  to  know  its  focal  length  we  divide  the  number  into 
40,  and  the  result  is  the  figure  desired.  If  we  have  the  focal 
length  and  want  the  number,  we  divide  40  by  the  focal  length 
and  the  result  is  the  number,  -f  2.50  is  of  16  inches  focal 
length,  because  2.50  is  contained  in  40  sixteen  times.  A  lens 
of  10  inches  focus  would  be  -}-  4.00  because  10  is  contained  in 
40  four  times. 

Lenses  are  not  made  in  smaller  fractions  than  eighths, 
so  that  when  a  figure  is  divided  into  40  and  the  result  is  not 
in  eighths  we  put  it  in  the  class  to  which  it  is  nearest.  For 
example,  a  15-inch  focus  would  give  number  2.66  2/3  when 
the  calculation  is  made  thus :  40  divided  by  15  equals  2.66  2/3. 
As  2.625  is  the  nearest,  we  so  class  it.  It  is  customary  to 
ignore  the  third  figure  in  the  decimal  expression,  so  the  num- 
ber would  be  2.62  or  2.63. 

In  practice  it  is  rarely  ever  necessary  to  use  smaller  frac- 
tions than  quarters,  because,  if  the  eye  is  below  normal,  so  that 
-|-  lenses  are  required,  it  should  be  given  full  correction,  or  a 
little  more;  and  if  it  is  above  normal,  so  that  —  lenses  are 
used,  it  should  be  undercorrected.  That  is,  if  +  1.12  is  called 
for  by  the  test,  give  +  1.25;  if  —  1.12  is  the  test,  give  —  1.00 

The  word  "dioptre"  means  "to  see  through,"  hence  it 
was  chosen  as  the  name  for  the  unit  of  measure  of  lenses. 


40 


OPTICAL  TRUTHS. 


As  has  been  shown  in  the  chapter  on  refraction,  —  lenses 
are  negative  quantities,  made  by  reversing  the  order  in  which 
prisms  are  used  for  +,  therefore,  the  numbering  applies  to 
both.     Also  to  cylinders. 

It  is  easy  to  tell  -f  from  — ,  because  if  a  +  lens  is  held 
between  the  eye  and  an  object  and  moved  back  and  forth  to 
right  and  left,  or  up  and  down,  or  moved  back  and  forth 
between  the  eye  and  the  object,  the  object  will  appear  to 
move  in  the  direction  opposite  to  that  in  which  the  lens  is 
moved,  and  the  stronger  the  lens  the  more  decided  the  motion. 
Take  —  lenses  and  the  motion  is  with  the  movement  of  the 
lens. 

Spherical  lenses  have  equal  power  in  all  meridians,  while 
cylindricals  have  power  only  when  moved  across  the  line  cor- 
responding to  the  axis.  To  find  the  axis  of  a  cylinder,  hold 
it  between  the  eye  and  some  straight  object  and  rotate  it. 
The  object  will  appear  distorted  in  shape  except  when  either 
the  axis  or  the  meridian  at  right  angles  to  the  axis  is  on  the 


fos\,JLj^ 


Fig.   30 


line  corresponding  to  the  correct  position  of  the  object.  Hav- 
ing found  that  position,  move  the  lens  sidewise  and  up  and 
down;  the  meridian  where  there  is  no  motion  to  the  object 
is  the  axis.  Make  a  mark  on  the  edge  of  the  lens  showing 
where  the  axis  is,  then  lay  the  lens  flat  on  Fig.  30,  center  over 
center,  and  read  the  meridian  from  the  figures.  The  inside 
of  the  lens  must  be  down  if  the  axis  is  oblique,  otherwise  an 
axis  which  is  really  60  will  register  120,  or  as  far  on  the  other 


PRESCRIPTION  WRITING.  41 

side  of  90 ;  axis  45  would  register  135 ;  axis  15  would  regfister 
165,  etc.,  or  lay  the  lens  on  Fig.  30  outside  down  and  have  an 
extra  set  of  figures,  reversed,  that  is,  begin  numbering  at  the 
left  and  number  toward  the  right.  If  it  registers  90  or  180 
it  is  as  registered  with  either  set  of  figures. 

Sphero-cylinders  will  cause  the  object  to  move  in  all 
directions,  but  in  one  meridian  there  will  be  the  greatest,  and 
in  the  one  at  right  angles  to  it,  the  least  motion.  Locate  the 
two  principal  meridians  as  described  in  the  case  of  cylinders. 

A  sphero-cylinder-prism  or  sphero-prism  lens  will  cause, 
not  only  the  movement  described  for  sphero-cylinders,  spheres 
or  cylinders,  but  the  prism  will  displace  the  object  towards 
its  apex.  The  prism,  base  reversed,  which  replaces  the  object, 
is  the  measure  of  the  prism  in  the  lens.  If  the  prism  in  the 
lens  is  base  in  it  will  require  the  same  degree  of  prism,  base 
out,  to  neutralize  it. 

A  prism  alone  will  not  distort  or  move  objects  seen 
through  them,  except  as  the  prism  is  rotated  it  will  hold  the 
virtual  object  in  perfect  shape,  constantly  in  line  with  the 
apex. 

To  ascertain  the  number  of  a  lens  use  lenses  of  the  opposite 
kind  which  have  the  numbers  on  them,  to  neutralize  the  one 
unknown.  If  a  +  lens  of  unknown  power  be  neutralized  with 
a  —  1.00  sphere  we  know  it  must  be  a  +  1.00.  If  a  -(-  1.00  cyl- 
inder axis  90  stops  all  motion  in  a  —  cylinder  we  know  it  must 
be  —  1.00  axis  90.  If  we  have  a  -f-  compound  (sphero-cylinder) 
and  —  1.00  —  1.50  axis  45  neutralizes  it,  we  know  it  is  +  1.00 
-f  1.50  axis  45.  If  it  is  a  compound  and  +  100  —  2.50  axis 
180  neutralizes  it  we  know  it  is  —  1.00  +  2.50  axis  180.  If  — 
1.50  +  2.50  axis  90  neutralized,  it  would  mfean  the  same. 
There  are  such  things  as  crossed-cylinders,  but  people  who  un- 
derstand their  business  never  have  any  use  for  them,  except  in 
the  very  rare  instances  where  the  astigmatic  error  is  so  great 
that  a  sphero-cylinder  would  give  more  spherical  and  chro- 
matic aberration.  Even  then,  the  sphero-toric  lens  (one  in 
which  there  is  a  spherical  curvature  on  one  surface,  and  both 


42 


OPTICAL   TRUTHS. 


a  spherical  and  cylindrical  curvature  on  the  other)  is  better 
in  most  cases.  It  is  a  fact,  however,  that  all  compound  lenses 
are  cross-cylinders  in  effect. 

One  of  the  most  important  features  of  optical  work  is  the 
writing  of  prescriptions  correctly,  yet  more  errors  are  com- 
mitted in  this  respect  than  in  any  other,  except,  possibly,  the 
prescribing  of  —  lenses  where  -f  should  be  used. 

The  incorrect  writing  does  not  affect  the  result  so  far  as 
the  patient  is  concerned,  but  it  frequently  involves  more  work 
for  the  optician  who  grinds  the  lenses.  For  example:  a  com- 
bination written  -(-  2.00  —  2.50  axis  180  means  a  -j-  spherical 
lens  is  combined  with  a  —  cylindrical  with  its  axis  at  180,  or 
the  horizontal  meridian. 

In  analyzing  this  we  must  remember  that  the  180  is  not 
a  lens,  but  is  the  particular  meridian  upon  which  the  axis  of 
the  cylinder  is  placed,  and  signifies  that  the  cylinder  has  no 
power  there.  Next,  we  must  remember  that  spherical  lenses 
have  power  in  all  meridians  equally,  so  the  power  of  the  com- 
bination on  the  horizontal  meridian  is  furnished  entirely  by 


—SO 


^2.00 


Fig-.    31 

the  spherical,  and  is,  of  course,  +  2.00,  Next,  the  other  prin- 
cipal meridian  is  always  at  right  angles  to  the  first,  which 
makes  it  the  90th  meridian;  on  this  line  both  lenses  have 
power,  and  as  one  is  -|-  while  the  otUer  is  — ,  the  real  effect  is 
only  the  difference  between  them.  The  —  being  2.50  while 
the  +  is  only  2.00,  the  balance  is  in  favor  of  the  —  by  .50,  so, 


PRESCRIPTION  WRITING.  43 

when  the  combination  is  made  into  a  lens  the  power  in  its  two 
principal  meridians  will  be  represented  by  Fig.  31. 

Had  the  prescription  been  written  —  .50  -)-  2.50  axis  90, 
the  effect  would  be  the  same,  because  now  the  axis  of  the  cyl- 
inder is  vertical,  and  it  has  no  power  on  its  axis,  while  the  — 
sphere,  having  power  in  all  meridians,  takes  full  effect  on  the 
vertical,  and  on  the  opposite  meridian  the  -|-  2.50  neutralizes 
the  —  .50  and  has  -f  2.00  remainder. 

An  easy  way  to  learn  the  difference  between  the  effects  of 
spheres  and  cylinders  is  to  make  a  drawing  like  Fig.  31,  which 
shows  only  the  90th  and  180th  meridians,  and  draw  oblique 
lines  through  the  center  to  designate  other  meridians,  say  the 
30th,  60th,  120th  and  150th,  then  on  the  one  where  the  axis 
of  the  cylinder  is  placed  put  "0"  and  on  the  one  at  right 
angles  to  it  put  the  power  of  the  cylinder,  then  on  the  lines  at 
either  side  of  the  axis  put  one-third  of  the  power  and  on  those 
at  either  side  of  the  meridian  where  the  full  power  is  recorded 
put  two-thirds  of  the  power,  then  make  another  figure  just 
like  it,  except  on  every  meridian  put  the  power  of  the  sphere ; 
thus  both  sides  of  the  lens  will  be  represented.  To  get  the 
full  power  of  the  lens  add  the  figures  representing  the  same 
meridians  if  the  signs  are  alike  and  subtract  if  the  signs  differ. 
In  practice  if  we  take  care  of  the  two  principal  meridians  nat- 
ural law  takes  care  of  the  rest. 

Manufacturing  opticians  carry  what  they  call  blank  cylin- 
ders in  stock :  that  is,  a  square  piece  of  glass  with  the  cylinder 
ground  on  one  surface,  and  grind  whatever  sphere  is  desired 
on  the  other  side,  then  lay  a  pattern  on  and  cut  the  lens  so 
the  axis  of  the  cylinder  is  at  the  proper  meridian.  In  the  pre- 
scription as  written  first  it  would  require  the  grinding  of  4- 
2.00  while  as  written  last  it  would  only  require  —  .50,  a  saving 
of  three-fourths  of  the  work.  If  all  practitioners  would  ob- 
serve these  points  it  would  facilitate  greater  speed  in  filling 
their  prescriptions  and  often  result  in  lighter  weight  lenses. 

The  following  examples  will  be  helpful  in  analyzing  and 
proving  correct  and  incorrect  prescription  writing: 


44 


OPTICAL   TRUTHS. 


+ 
+ 


1.00 
.50 
1.00 
1.00 
2.00 
1.00 
1.00 
1.00 
1.00 
1.50 


4-  1.00  — 


-f  1.00  ax. 
4-  1.50  ax. 
4-     .75  ax. 

—  2.00  ax. 

—  1.50  ax. 

—  1.00  ax. 

—  2.00  ax. 
-\-  2.00  ax. 

3.00  ax. 
4.00  ax. 


+ 


90 

45 

60 

120 

75 

150 

135 

165 

180 

140 


or  any  other  axis,  would 
be  correct,  because  the 
^  signs  are  alike ;  or,  dif- 
f ering,  tfie  cylinder  is  at 
least  twice  as  strong  as 
the  sphere. 


+  1.00  — 


1.00 
1.50 
1.00 
1.00 


.50  ax. 
2.00  ax. 

.75  ax. 
1.50  ax. 


60 

180 

90 

45 


or 


are 


any    other    axes, 
j  wrong,  because  the  signs 
).  differ,    and  the   cylinders 
I  are    less    than    twice    as 
j  strong  as  the  spheres. 
The  meridian  given  as  the  location  of  the  axis  of  the  cylin- 
der is  called  the  first  principal  meridian  and  the  one  opposite 
to  it  is  the  second  principal  meridian. 

As  lenses  are  to  supply  deficiencies  and  neutralize  over- 
developments of  the  dioptric  systems  of  the  eyes,  it  is  in  order 
to  explain  some  of  the  physical  qualities  of  those  organs  here. 


Fig.   32 


Normal  and  defective  eyes  are  named,  respectively,  emmetropic 
and  ametropic.  The  latter  are  divided  into  two  classes,  the 
deficient  ones  are  hypermetropic,  or  hyperopic,  while  the  over- 
developed ones  are  myopic.  The  first  are  sometimes  called 
far-sighted  and  the  latter  near-sighted. 

Fig.  32  shows  how  the  retina  of  the  emmetropic  eye  is 
situated  at  the  principal  focus  of  the  dioptric  system.  This 
eye  requires  no  lens  because  its  focus  ia  correct  without  it. 


PRESCRIPTION  WRITING.  45 

Fig.  33  shows  the  retina  of  a  hyperopic  eye  in  front  of  the 
principal  focus,  because  the  eye  is  too  short  on  its  axis,  or  be- 


Fig.   33 

cause  the  cornea  or  lens,  or  both,  are  of  deficient  curvature. 
This  eye  needs  a  -f  lens  to  shorten  the  focus  by  increasing  the 
power  of  the  apparatus. 

Fig.  34  shows  the  retina  of  a  myopic  eye  behind  the  prin- 
cipal focus,  because  the  eye  is  too  long  on  its  axis,  or  because 


Fig.   34 


the  cornea  or  lens,  or  both,  are  of  too  great  curvature.  This 
eye  needs  a  —  lens  to  lengthen  the  focus  by  neutralizing  the 
excess  power  of  the  dioptric  system. 

In  many  cases  the  cornea  is  not  of  spherical  curvature, 
but  is  not  irregular,  and  it  is  one  of  Nature's  laws  that  all 
non-spherical,  regular  curvatures  have  two  principal  meridi- 
ans, at  right  angles  to  each  other.  In  architecture  such  a  sur- 
face is  called  toric.  It  is  well  illustrated  by  a  bicycle  tire 
which  has  a  long  curve  around  the  wheel  and  a  short  one 
around  the  tire.  Imagine  a  piece  of  glass  like  that  and  it  is 
easy  to  see  the  shortest  curve  would  focus  sooner  than  the 
long  one,  hence  if  light  was  permitted  to  pass  through  the 
v/hole  surface  of  a  lens  at  once  there  would  be  no  focus. 

Let  Fig.  35  represent  the  curves  of  the  two  principal  me- 


46 


OPTICAL   TRUTHS. 


Fig.    35 

ridians  of  a  lens,  A  being  the  vertical  and  B  the  horizontal. 
The  rays  1  and  1  would  focus  at  1  and  the  rays  2  and  2  would 
focus  at  2.  This  lack  of  common  focus  is  called  astigmatism, 
meaning  without  a  point.  When  an  eye  presents  such  a  sur- 
face to  rays,  vision  is,  of  course,  more  or  less  impaired,  owing 
to  the  amount  of  the  difference  between  the  two  principal 


3.  Hy,fist. 


S.fVlLj.  fist. 


+  Cul 


-Cijl. 


CoM.Hy.  f\&t. 


+  Sph. -t-Cij(, 


Com. My.  f[st. 
Mixed  fist. 


^Suh.  -Qui. 


-Sph.+  Cyl. 
+  SpK.  -  Cyl. 


Fig.   36 


PRESCRIPTION  WRITING.  47 

meridians;  sometimes  there  is  so  little  difference  it  is  not 
worth  correcting,  as  will  be  shown  in  the  chapter  on  measuring 
errors  of  refraction. 

There  are  five  different  forms  of  regular  astigmatism: 
Simple  and  compound  hyperopic,  simple  and  compound  myopic 
and  mixed.  Fig  36  shows  the  principal  focal  points  of  the 
two  principal  meridians  in  each  case;  the  myopic  meridians 
focus  too  soon,  the  normal  ones  at  the  line  R,  and  the  hyperopic 
ones  beyond  the  line;  the  first  ones  require  —  lenses,  the  sec- 
ond, none,  and  the  third,  -j-  lenses ;  the  amount  of  astigmatism 
is  the  distance  between  the  two  points.  In  mixed  astigmatism 
one  meridian  is  myopic  and  the  other  hyperopic. 

Having  seen  that  a  cylindrical  lens  has  no  power  on  its 
axis,  we  have  a  law  by  which  we  analyze  compound  prescrip- 
tions, and  it  is  essential  to  practice  that  it  be  understood  per- 
fectly, because  by  our  method  of  fitting  with  or  without  cyclo- 
plegics  we  must  nearly  always  transpose  the  prescription,  as  it 
comes  from  the  trial  frame,  to  put  it  in  its  simplest  form. 
Sometimes  it  comes  from  the  frame  a  compound  and  we  trans- 
pose it  into  a  simple  cylinder.  The  two  principal  meridians, 
when  drawn  on  paper  form  a  cross,  hence,  in  proceeding  by  the 
law  we  do  one  step  at  a  time. 

1st  step:  Draw  a  line  representing  the  meridian  desig- 
nated as  the  axis  of  the  cylinder. 

2nd  step:  Write  at  one  end  of  that  line  the  sign  and 
power  of  the  sphere,  because  it  is  the  only  part  of  the  combina- 
tion that  has  power  (viz.,  curvature),  there. 

3d  step:  Draw  a  line  representing  the  other  meridian 
which  is  always  at  right  angles  to  the  first  and  is  90  degrees 
from  it  on  the  circle ;  if  the  first  is  below  90,  add  90  to  find  the 
degree;  if  the  first  is  above  90,  subtract  90.  Thus  if  the  first 
is  40  the  second  will  be  130 ;  if  the  first  is  120,  the  second  will 
be  30,  etc. 

4th  step:  Write  at  one  end  of  the  second  line  the  effect 
of  the  two  lenses ;  if  both  are  4-  or  both  are  — ,  add  the  figures 
and  give  the  sign;  if  one  is  -\-  and  the  other  — ,  subtract  the 


48  OPTICAL  TRUTHS. 

less  from  the  greater  and  use  the  remainder,  giving  the  sign 
of  the  greater;  if  the  signs  differ  but  the  power  is  equal  of 
course  there  is  nothing  to  be  recorded  and  we  put  it  "  0. " 

5th  step :  Make  a  diagram  of  the  focal  points  of  the  two 
meridians  as  shown  in  Fig.  36. 

6th  step :  Begin  writing  the  new  prescription  by  writing, 
for  the  spherical  part,  -f  or  — ,  whatever  is  needed  for  the 
meridian  nearest  normal. 

7th  step:  Change  the  focal  point  to  the  line  R,  as  the 
lens  would  do  it,  and  change  the  focal  point  of  the  other  me- 
ridian the  same  amount  in  the  same  direction. 

8th  step :  Write  for  the  cylindrical  part,  +  or  —  cylinder 
of  sufficient  power  to  put  the  other  meridian  on  the  line  R  also 
and  write  for  the  axis  the  number  of  the  meridian  corrected 
by  the  sphere. 

This  law  always  works.  If  a  prescription  is  written  cor- 
rectly it  will  prove  it,  and  if  wrong  it  will  correct  it.  To  prove 
the  correctness  of  a  transposition  put  the  new  prescription  on 
a  cross  by  steps  1,  2,  3,  4,  then  if  it  corresponds  with  the  cross 
made  from  the  original  prescription  and  the  cylinder  is  still  of 
the  same  power,  it  is  proved. 

A  short  way  to  transpose  a  prescription  that  needs  it  is  to 
take  the  difference  between  the  powers  of  sphere  and  cylinder 
for  the  new  sphere,  then  use  the  power  of  the  old  cylinder,  but 
change  the  sign  and  reverse  the  axis. 

No  prescriptions  need  transposing  unless  the  signs  differ 
and  the  cylinder  is  less  than  twice  as  strong  as  the  sphere. 

It  is  always  a  case  of  mixed  astigmatism  when  the  signs 
differ  and  the  cylinder  is  the  least  bit  stronger  than  the  sphere. 

It  is  always  a  case  of  simple  astigmatism  when  the  signs 
differ  and  the  cylinder  is  of  the  same  power  as  the  sphere. 

It  is  always  a  case  of  compound  astigmatism  when  the 
signs  differ  and  the  cylinder  is  weaker  than  the  sphere. 

The  following  examples  will  show  the  process  of  working 
out  transpositions :  Some  people,  who  want  to  be  mysterious, 
write  a  prescription  like  this: 


PRESCRIPTION  WRITING. 


49 


+D.  S.  1.00  C  +D.  C.  2.00  ax.  90. 
D.  for  diopter,  S.  for  sphere,  C  for  combined  with,  D.  for 
diopter,  C.  for  cylinder.  We  know  that  the  first  lens,  having 
no  axis  written,  must  be  a  sphere,  and  the  other  having  an 
axis,  is  a  cylinder.  Being  written  together,  a  compound  is 
intended,  thus,  +  1.00  -f  2.00  ax.  90. 

^^-^^iu><  ^^^'  Condition  of  etfe. 

R 


.■I-3.0O 


\  3.00 


Fig.  37 

Following  the  law,  step  by  step,  the  prescription  comes 
out  as  it  went  in,  hence  must  be  correct,  and  by  Fig.  37  we  see 
it  is  compound  hyperopic  astigmatism. 

Another,         L.  -f  3.50  —  3.50  ax.  180 
R.   4-  4.00  —  5.00  ax.  30. 

0 


-<-3.iro 


sro 


+  W.ffO 


Fig:. 


50 


OPTICAL   TRUTHS. 


The  left  eye  shows  (Fig.  38)  the  90  meridian  is  normal, 
so  we  write  for  it  a  simple  cylinder,  -|-  3.50  ax.  90,  because  we 
must  have  the  power  at  180  and  the  power  of  cylinders  is 
always  across  the  axis.  For  the  right  eye  we  write  —  1.00, 
which  puts  the  120th  meridian  on  the  line  but  drives  the  other 
1.00  farther  away  so  it  must  now  have  -j-  5.00  cylinder,  ax. 
120,  hence  the  prescription  will  read  —  1.00  -f  5.00  ax.  120. 
That  for  the  left  eye  shows  simple  hyperopic  astigmatism, 
while  the  right  shows  a  case  of  mixed  astigmatism. 

Another,  —  2.00  —  1.00  ax.  180. 


Jjf/ect  of  ^e/zs 


Condition  of  ej^e 


"S.OQ 


£ffectufje72s 


Fig-.   39 

Analysis  shov/s  the  original  to  be  correct  and  Fig.  39  shows 
compound  myopic  astigmatism. 

Another,  -f  2.00  —  3.00  ax.  135. 

ConditiQfVof'ej/e 

100 

cf 


Fig.   40 


Ji.OO 


PRESCRIPTION  WRITING. 


5J 


Analysis,  (Fig.  40)  shows  —  1.00  -\-  3.00  ax.  45,  a  case  of 
mixed  astigmatism. 

Another,  —  5.00  ax.  180. 

Being  a  simple  cylinder  of  course  there  is  no  transposition. 
A  case  of  simple  myopic  astigmatism,  Fig,  41. 

s:oo  ^ 


rjroo 


Fig.   41 

Another,  L  +  1.50  —  3.00  ax.  155. 
R  +  1.00  —  1.00  ax.  180. 


left 


-f  /.fo 


-.'TO 


/?/y^t. 


)>"« 


+^(.00 


-h/.ffO 


Fig-.    42 

Corrected,  Fig.  42,  L.  —  1.50  +  3.00  ax.  65. 
R.  +  1.00  ax.  90. 
Don't  forget  that  transposing  prescriptions  and  neutraliz- 
ing lenses   are   two  different  propositions.    In   neutralizing, 
change  signs  but  not  axes.    If  —  and  +  errors  are  equal,  as 
in  L.,  Figure  42,  use  —  spheres  and  +  cylinders. 


THE  EYES  AS  DOUBLE  GAUGES. 

How  to  Measure  the  Nerve  and  Blood  Supplies  Through  Them. 

The  eyes  are  to  the  human  body  what  the  gauges  are  to 
boilers  and  electric  plants.  With  an  ophthalmoscope  the  doc- 
tor who  knows  how  can  look  inside  the  eyes  and  observe  both 
the  arterial  and  venous  systems,  note  the  quality  and  quantity 
of  the  blood,  thus  learning  what  the  blood-making  and  purify- 
ing organs  are  doing  without  inconvenience  to  his  patient. 
There  are  many  other  things  he  may  learn,  too,  as  will  be 
shown  under  the  proper  headings  further  along  in  this  work. 
Few  oculists,  scarcely  any  physicians  and  no  faith  healers 
know  the  value  of  this  simple  little  instrument.  So  simple, 
indeed,  that  an  ordinary  lens  with  one  side  plane,  or  slightly 
concave,  is  a  very  practical  ophthalmoscope.  The  eyes  are, 
therefore,  the  blood  gauges  of  the  body. 

The  doctor  who  knows  how  can  apply  dynamic  and  static 
tests  through  the  eyes  and  measure  the  amount  of  the  nerve 
supply  just  as  perfectly  as  the  steam  gauge  or  amperemeter 
tells  the  pressure  of  steam  or  the  quantity  of  electricity  being 
consumed  each  day,  hour  or  minute.  Thus  the  eyes  are  the 
steam  gauges  and  amperemeters  of  the  body.  No  doctors, 
excepting  my  own  pupils,  have  known  this  because  I  was  the 
fortunate  person  who  discovered  it.  I  have  compiled  data, 
tables,  etc.,  and  named  them  "The  Neurometer"  (nerve  meas- 
ure) .  They  will  be  found  in  the  regular  order  of  my  story,  and 
those  who  master  them  will  find  them  so  accurate  that  after  a 
complete  examination  they  can  figure,  very  closely,  the  pa- 
tient's age.  If  this  sounds  incredible,  think  what  a  fool  I 
would  be  to  make  the  assertion  if  it  were  not  true. 

The  schematic  eye.  Fig.  44,  is  made  to  a  scale,  each  five 
millimeters  representing  one,  so  that  it  represents  an  enlarge- 
ment of  twenty-five  times,  the  regularly  accepted  dimensions 
for  an  ideal  eye  being: 


54 


OPTICAL   TRUTHS. 


Radius  of  curvature  of  cornea,  7.8  millimeters. 
Distance  of  anterior  of  lens  from  cornea,  3.6  millimeters. 
Radius  of  anterior  surface  of  lens,  10.  millimeters. 
Distance  of  posterior  of  lens  from  cornea,  7.2  millimeters. 
Radius  of  posterior  surface  of  lens,  6  millimeters. 


THE  EYES  AS  DOUBLE  GAUGES.        55 

Distance  of  posterior  of  globe  from  cornea,  22.5  milli- 
meters. 

Radius  of  globe,  10.8  millimeters. 

The  normal  eye  is  9/10  in.  long,  8/10  in.  wide,  7/10  in.  high, 
approximately  45.  diopters  power. 

The  reference  figures  indicate : 

1.  Conjunctiva:  a  delicate  membrane  composed  of 
minute  blood  vessels  and  nerves  with  just  enough  connective 
tissue  to  complete  the  structure.  It  covers  the  front  of  the 
eye,  as  shown,  then  laps  back  inside  the  lids,  forming  a  lining, 
and  serves  the  double  purpose  of  furnishing  the  soft  surfaces, 
which,  when  lubricated  by  the  tears,  prevent  friction  from 
winking,  and  being  highly  sensitive,  it  protects  the  eye  by 
giving  quick  warning  of  the  presence  of  foreign  substances. 
It  is  a  great  exaggerator,  always  declaring  the  smallest  par- 
ticle is  a  whole  brick. 

2.  Cornea:  the  projecting  transparent  portion  forming 
about  one-sixth  of  the  outer  wall  of  the  eye.  It  is  of  cellular 
structure  with  tough  surfaces  so  nearly  like  horn  that  its  name 
was  given  on  account  of  the  resemblance.  It  is  transparent 
so  light  may  pass  into  the  interior,  and  its  radius  of  curvature 
is  shorter  than  the  main  globe  in  order  to  give  the  whole  eye 
more  focusing  power,  for  remember  in  all  optical  literature 
curvature  means  power,  and  the  sharper  the  curve  the  greater 
the  power,  consequently  the  quicker  will  rays  of  light  focus 
after  passing  it. 

3.  Iris:  the  projections  from  the  margin  of  the  cornea; 
the  space  between  the  two  figures  represents  the  pupil,  which 
appears  to  the  observer  as  a  black  spot  in  all  eyes.  Some, 
even  doctors,  call  it  the  '  *  sight ' '  of  the  eye.  It  is  the  hole  in 
the  iris  or  curtain,  through  which  light  must  pass  to  get  back 
to  the  posterior  wall,  where  the  "sight"  spot  is.  The  curtain  is 
formed  by  combining  a  great  number  of  straight  ligaments 
with  a  circular  muscle,  and  the  whole  thing  would  be  like  a 
lace  curtain  were  it  not  for  the  pigment  filling,  represented 
by  the  dashes.    This  pigment  gives  it  color;  the  more  pigment 


56  OPTICAL  TRUTHS. 

the  darker  the  color.  Close  observation  shows  a  variety  of 
colors  in  the  same  curtain,  hence  the  name  iris,  which  means 
rainbow.  If  the  nervous  connections  are  normal  it  is  under 
command  of  the  retina,  or  optic  nerve,  and  regulates  the 
amount  of  light  admitted.  The  ligaments  run  from  the  edge  of 
the  pupil  outward,  while  the  circular  muscle,  sphincter,  it  is 
called,  being  the  only  one  supplied  with  nerves,  reduces  the 
pupil  by  contracting,  thus  pulling  the  inner  ends  of  the  liga- 
ments together;  or,  enlarges  it  by  relaxing  its  efforts.  Some 
very  ridiculous  stories  have  been  told  about  this  curtain. 

4.  Aqueous  humor:  fills  all  the  space  between  2  and  5 
and  the  iris  floats  in  it.  It  is  briny,  cool  and  is  rarely  the  seat 
of  trouble — a  good  hint  from  Nature  about  salt. 

5.  Anterior  capsule  of  crystalline  lens:  the  posterior  one 
is  not  numbered  because  the  one  figure  is  enough  for  both. 
They  enclose: 

6.  Crystalline  humor,  which,  while  a  liquid,  is  con- 
structed in  layers,  nearly  like  an  onion.  The  lens  includes  the 
capsules  and  humor  and  is  held  in  position  by  a  combination 
similar  to  that  described  for  the  iris,  only  larger  and  more 
powerful,  for,  instead  of  a  hole,  as  the  iris  has,  the  lens  is  there 
to  be  operated,  its  power  being  increased  by  pressure  around 
its  edge  which  forces  shorter  radii  of  curvature.  This  func- 
tion was  intended  for  adapting  normal  eyes  to  near  points. 
Rays  from  as  far  as  twenty  feet  or  more  distant  are  so  nearly 
parallel  that  the  normal  eye  focuses  them  with  very  slight 
effort,  but  when  they  come  from  points  nearer  they  are  decid- 
edly divergent,  which  forces  the  eye  to  increase  its  focal  power 
if  it  would  see  distinctly.  There  is  a  little  canal  around  the 
edge  of  the  lens,  which  I  call  a  bicycle  tire,  for  simplicity  of 
illustration,  a  hollow  tube  filled  with  liquid  which  makes  it 
very  elastic,  especially  in  young  and  middle  aged  people;  this 
tire  is  attached  to  or  rather  formed  by  the  suspensory  liga- 
ments, and  pulls  against  them  almost  enough  to  overcome 
them,  but  not  quite,  so  that  the  lens  remains  at  its  lowest 
power  except  when  the  sphincter  muscle  comes  to  the  aid  of 


THE  EYES  AS  DOUBLE  GAUGES.        57 

the  tire  and  accomplishes  what  is  called  accommodation  for 
near  points.  When  the  necessity  ceases  the  sphincter  lets  go 
and  the  suspensory  ligaments  pull  the  lens  back  to  its  original 
static  or  natural  condition.  As  we  grow  older  the  tire's  con- 
tents shrink  so  that  it  is  no  longer  so  elastic  and  the  sphincter 
muscle,  not  being  able  to  do  all  the  work,  fails  to  focus  light 
from  near  points  at  the  retina  and  glasses  have  to  be  used  for 
reading  on  eyes  which  are  otherwise  perfect.  As  this  is  an 
incident  of  old  age,  it  is  called  presbyopia.  When  you  see 
people  who,  after  using  reading  glasses  for  a  while,  also  put 
some  on  for  improvement  of  distant  vision,  you  will  know 
they  never  had  perfect  eyes,  although  they  may  have  had  per- 
fect vision.  The  story  of  eyes  "flattening"  from  old  age  is 
another  story  that  isn't  true. 

7.  Hyaloid  membrane :  a  layer  with  a  past.  It  originally 
entered  the  eye  at  "E"  as  a  canal  and  passed  straight  to  the 
center  of  the  posterior  capsule  of  the  lens,  carrying  the  mate- 
rial from  which  the  lens  was  constructed;  when  that  job  was 
finished  it  expanded  and  enclosed  the  vitreous  humor  (8), 
which  fills  the  globe.  That  this  humor  is  nourished  by  way 
of  the  same  old  channel  there  can  be  no  doubt,  because  when 
patients  come  complaining  of  floating  specks  we  change  their 
diet,  when  the  specks  disappear. 

The  layer  next  outside  of  the  hyaloid  membrane  is  the 
retina,  comprising  a  network  of  nerves  and  blood  vessels,  the 
nerves  being  branches  of  the  optic,  or  second  cranial.  Its 
function  is  to  transmit  impressions  to  the  brain,  and  its  struc- 
ture is  complex  microscopically,  which,  however,  is  not  a  nec- 
essary detaU  of  this  part  of  my  story.  One  of  its  layers,  that 
of  rods  and  cones,  has  to  do  with  the  next  general  layer,  repre- 
sented by  the  dash  lines,  which  is  of  honeycomb-like  structure, 
the  cells  being  filled  with  pigment.  This  layer  is  for  the  pur- 
pose of  receiving  and  absorbing  excessive  light,  thus  prevent- 
ing injury  to  the  retina  which  would  interfere  with  vision. 
This  layer  also  extends  into  the  iris,  giving  it  its  color. 

The  next  layer  is  the  choroid:  it  carries  the  blood  vessels 


€0  OPTICAL   TRUTHS. 

and  nerves  which  nourish  and  furnish  motive  power  to  the 
sphincter  muscles  of  the  ciliary  body  and  iris.  The  ciliary 
body  is  composed  of  folds  of  the  choroid  and  is  marked  "9"  in 
the  illustration.  This  drawing  shows  the  lower  half  of  a  right 
eye,  as  if  it  was  bisected  horizontally.  The  suspensory  liga- 
ments marked  "  10, "  radiate  from  the  edge  of  the  lens  and  are 
rooted  firmly  in  the  ciliary  body. 

The  outside  layer,  extending  from  the  cornea  to  "E,"  is 
the  sclerotic  (hard),  a  layer  of  protection,  its  structure  being 
fibrous  and  tough;  in  it  are  inserted  the  six  muscles  which 
control  the  motion  of  the  eyeball.  All  of  these  muscles  have 
their  origin  within  the  orbits,  the  cavities  in  the  skull  in  which 
the  eyes  are  set;  four  of  them  pass  straight  up  over,  under 
and  on  either  side  branching  out  until  they  cover  the  whole 
eyeball  almost  to  the  edge  of  the  cornea,  their  function  is  to 
move  the  eyeballs ;  the  other  two  pass  forward  on  the  side  next 
the  nose,  then  turn  and  pass  over  and  under  the  globe  and  a 
little  obliquely  backward.  Their  function  is  to  prevent  the 
eye  from  rolling  on  its  axis,  which  is  represented  by  the  line 
drawn  through  the  center.  This  line  is  called  the  optical  axis ; 
the  old  school  books  teach  there  is  also  a  visual  axis,  which 
crosses  this  one  obliquely,  but  that  story  is  like  many  others 
by  the  same  writers,  decidedly  oblique,  as  I  will  show. 

"  E "  is  the  gateway  through  which  the  retinal  vessels  and 
nerves  enter  and  emerge.  In  all  eyes  the  space  shown  is  not 
sensible  to  light  impressions  because  the  retina  cnly  begins  at 
its  edge,  hence  it  is  called  the  "blind  spot."  Outside  of  the 
space  marked  "E"  is  a  zone  in  which  the  vessels  which  supply 
the  choroid  pierce  the  sclerotic  coat,  which  has  no  vessels  or 
nerves  of  its  own.  The  spot  marked  "E"  is  on  the  inner  half 
of  the  eye,  but  is  half  way  between  the  top  and  bottom.  The 
field  around  the  posterior  pole  extending  from  the  blind  spot 
to  an  equal  distance  beyond  the  axis  is  more  highly  sensitive 
than  other  parts,  because  images  of  all  objects  seen  clearly  are 
formed  there ;  this  field  has  been  considered  important  enough 
to  be  named,  so  it  was  called  "macula,"  meaning  "spot,"  and 


THE  EYES  AS  DOUBLE  GAUGES. 


59 


a  German  who  wanted  to  get  ahead  of  his  colleagues  imagined 
he  could  distinguish  a  decidedly  yellow  color  in  it,  and  he 
added  the  word  "lutea,"  meaning  "yellow."  His  victims 
adopted  his  statement  and  have  ever  since  reiterated  the  false- 
hood, thus  affording  opportunity  for  practical  students  to  see 
how  little  such  writers  are  worth  as  authorities. 


Fig.    45 

Fig.  45  shows  the  relation  between  the  two  eyes  and  the 
arrangement  of  the  muscles  which  arise  from  a  cartilaginous 
substance  in  the  orbits  just  behind  the  eyes. 

1-1.  External  recti,  operated  by  6th  nerves,  turn  eyes 
outward. 

2.  Inferior  rectus,  operated  by  3rd  nerves,  turns  eye 
down. 

3.  Inferior  oblique,  operated  by  3rd  nerves,  prevent  eyes 


60  OPTICAL  TRUTHS. 

rolling  inward  at  the  top  and  outward  at  bottom,  around  axes. 
4-4.    Internal  recti,  operated  by  3rd  nerves,  turn  eyes  in, 
associated  automatically  with  accommodation. 

5.  Superior  oblique,  operated  by  4th  nerves,  prevents 
eyes  rolling  inward  at  bottom  and  outward  at  top,  around 
axes. 

6.  Superior  rectus,  operated  by  3rd  nerves,  turns  eye  up. 

7.  The  optic  or  2d  nerve,  to  the  retina. 

8.  Optic  nerve  commissure,  or  switch-yard  where  the 
nerves  cross  over  and  divide;  the  macula  of  the  right  eye  is 
supplied  by  the  left  nerve  and  that  of  the  left  eye  by  the 
right  nerve. 

9.  Optic  nerve  sheath,  for  protection. 

The  lids  or  palpebrae,  comprise  superior  and  inferior  tar- 
sal cartilages  areolar  or  connective  tissue,  the  skin  and  the 
conjunctiva. 

The  muscles  of  the  lids  are: 

Corrugator  supercilli;  3d  nerves;  draw  brows  down  and 
in. 

Levator  palpebrae  superioris;  3rd  nerves;  lift  upper  lids. 
Originates  with  muscles  of  orbit. 

Orbicularis  palpebrarum ;  7th  nerves ;  to  close  lids. 

Tensor  tarsi ;  7th  nerves ;  press  the  edges  of  lids  to  globe, 
retaining  and  distributing  lachrymal  lubrication. 

The  Meibomian  glands  traverse  the  tarsal  cartilages  and 
connect  with  ducts  to  the  free  margin  of  the  lids.  They  are 
most  plentiful  in  the  upper  lids  and  their  function  is  to  carry 
off  accumulations  from  the  lachrymal  fluid  which  penetrate 
the  conjunctiva. 

The  lachrymal  glands  are  situated  at  the  upper  outer  an- 
gles of  the  orbits  and  supply  fluid  for  lubrication.  It  passes 
away  through  the  lachrymal  canals,  at  the  inner  angles  of  the 
eyes  into  the  nasal  ducts. 

The  blood  supply  of  the  eyes  and  lids  comes  from  the 
ophthalmic  arteries,  which  are  branches  of  the  internal  caro- 
tids, branches  of  innominate  and  left  common  carotid,  branches 


THE  EYES  AS  DOUBLE  GAUGES. 


6i 


of  the  aorta,  from  the  heart.  It  leaves  the  eyes  through  the 
ophthalmic  veins  to  canals,  in  the  base  of  the  skull,  which  con- 
nect with  the  internal  jugular,  thence  to  the  subclavian,  innom- 
inate, superior  vena  cava  and  heart. 


Fig.    46 


Fig.  46  shows  how  refraction  occurs  at  the  cornea  and  at 
both  surfaces  of  the  lens.  A  is  the  principal  axis,  R  is  the  ray 
approaching  from  infinity  parallel  with  the  axis,  P^  is  the  per- 
pendicular to  the  cornea,  P-  the  perpendicular  to  the  anterior 
surface  of  the  lens,  P^  the  perpendicular  to  the  posterior  sur- 
face of  the  lens.  Assuming  that  the  entire  eye  is  of  one 
density  and  that  equal  to  glass,  index  1.50,  the  angle  marked 
1  1/2  outside  and  the  one  marked  1  on  the  inside  would  indi- 
cate the  course  to  be  on  the  lower  line  to  the  retina;  as  a 
matter  of  fact  the  ray  follows  the  upper  line,  requiring  three 
calculations  to  carry  it  through  cornea  and  lens,  but  I  have 
made  both  lines  to  show  that  as  a  time  and  work  saver  the 


62  OPTICAL   TRUTHS. 

coincidence  is  a  happy  one,  because  either  gives  the  same  result 
practically.  To  make  the  real  course  the  angle  outside  of  the 
cornea  is  to  the  one  inside  as  4  is  to  3  because  the  index  of  the 
cornea  and  aqueous  is  1.33  13,  while  the  air  is  1.00;  then  the 
angle  outside  the  lens,  in  the  aqueous,  is  to  that  in  the  lens  as 
21  is  to  20  because  1.40,  the  index  of  the  lens,  is  to  1.33  1/3,  the 
index  of  the  aqueous,  as  these  figures  are  to  each  other.  It  is 
found  in  this  way;  1.33  1/3=4/3;  1.40=7/5;  reduced  to  a 
common  denominator  the  former  is  20/15  and  the  latter  21/15. 
The  larger  angle  being  in  the  rarer  medium  the  figures  re- 
verse, of  course.  Then  in  passing  the  posterior  surface  of  the 
lens  the  angles  are  as  20  is  to  21,  the  larger  angle  being  in  the 
vitreous  humor.  Make  the  drawing  on  a  scale  of  1  inch  for  a 
millimeter,  according  to  the  figures  given  on  another  page  and 
the  magniJacation  will  maJie  the  points  clear. 

This  is  called  the  static  refraction  of  the  eye  because  the 
muscles  controlling  the  lens  are  at  rest.  As  this  eye  focuses  at 
the  retina  it  must  be  emmetropic. 

The  alleged  ' '  old  masters, ' '  who  wrote  works  on  the  eyes, 
had  a  lot  of  idols  they  worshiped,  for  with  them  they 
were  able  to  mystify  their  readers  into  accepting  them  as  au- 
thorities because  they  were  incomprehensible.  Fig.  47  shows 
one  of  these  idols,  naked.  The  lines  0  ax  are  the  optical  axes 
because  they  pass  from  pole  to  pole  through  all  the  principal 
points;  the  lines  V  ax  show  what  they  called  the  visual  axes. 
They  insisted  these  were  necessary  because  when  the  eyes  are 
completely  at  rest  the  optical  axes  must  be  parallel,  hence  we 
would  see  double  were  it  not  for  those  visual  axes  which  they 
described  as  secondary  axes,  necessarily.  Of  course  their  claim 
was  purely  theoretical,  and,  had  they  given  the  matter  a  second 
thought  they  would  not  have  made  it  because  no  eye,  emme- 
tropic or  hyperopic,  can  be  at  rest  absolutely  when  looking  at  a 
distance  for  the  reason  that  while,  for  the  purpose  of  illustra- 
tion, we  assume  the  rays  approach  the  eyes  parallel  when  they 
come  from  infinity  they  are  really  a  trifie  divergent,  and  for 
the  same  reason  that  a  pair  of  perfect  eyes  in  looking  at  a 


THE  EYES  AS  DOUBLE  GAUGES. 


63 


point  40  inches  distant,  accommodate  1.00  D.  each  and  con- 
verge .50  each,  they  must  accommodate  for  an  80-inch  point 
.50  each  and  converge  .25  each  and  for  one  mile  each  would 
have  to  accommodate  1/1600  of  a  diopter  and  converge 
1/3200.  In  maintaining  the  ratio  of  .50  convergence  to  1.00 
accommodation  for  all  points,  near  or  far,  it  is  clear  that  no 


^ 


Fig.   4i 


64  OPTICAL  TRUTHS. 

separate  "visual"  aoces  are  necessary,  and  if  there  were  such 
things  they  would  cause  incoordination.  Therefore,  that  story 
is  on  a  par  with  the  other  one  they  tell  about  the  displaced 
macula,  as  if  it  slipped  around  like  a  disjointed  bone. 

While  we  are  breaking  idols,  let  us  smash  another.  Fig. 
48  shows  the  line  X  V  F  as  the  visual  axis;  the  line  A  0  the 
optical  axis ;  the  line  X  C  the  "line  of  fixation" ;  N  N  the  nodal 
points;  the  line  N  E  the  "major  axis  of  the  corneal  ellipsoid," 
and  C  the  center  of  rotation.  They  tell  us  the  angle  formed 
by  the  line  of  fixation  and  the  optical  axis  X  C  A,  is  the  ' '  angle 
gamma,"  and  that  formed  by  the  "visual  axis"  and  the 
"major  axis,"  X  N  E,  is  the  angle  alpha.  That  was  certainly 
Greek  enough  for  the  most  exacting  (Landolt  apologizes  for 
it,  explaining  that  his  drawing  is  "very  schematic"),  but  un- 
fortunately it  is  &  false  proposition  for  the  reason  given  with 
reference  to  Fig.  47  where  it  is  shown  that  there  is  no  visual 
axis  separate  from  the  optic  axis,  because  none  is  needed,  henct 
the  smashing  of  the  one  idol  kills  the  other. 

The  relation  of  accommodation  to  convergence  causes 
trouble  when  there  are  errors  in  the  dioptric  systems  of  the 
eyes  because  the  hyperopic  eyes  need  the  accommodation  but 
not  the  convergence  for  distant  objects,  and  they  need  more  ac- 
commodation for  near  points  than  goes  normally  with  the  con- 
vergence necessary,  while  the  myopic  eyes  cannot  see  at  a 
distance  because  their  far  points  are  nearer  than  infinity,  and 
when  the  object  is  brought  near  enough  to  see  they  need  the 
convergence  without  the  accommodation  that  normally  goes 
with  it,  therefore,  in  both  instances  there  is  in-coordination. 
In  the  hyperope  the  ability  to  compensate  or  adapt  the  organs 
to  the  situation  is  supplied  by  way  of  the  6th  nerves  to  the 
external  recti  which  antagonize  the  intemi  to  the  extent  of 
maintaining  parallelism  of  the  axes,  so  that  binocular  vision 
is  afforded,  but  the  strain  on  the  nerve  supply  is  enormous. 
Each  diopter  of  accommodation  being  accompanied  by  .50  con- 
vergence, requires  at  least  .50  negative  pull  via  the  6th  nerves, 
making  the  total  demand  on  the  nerve  supply  2.  D.     Thus  a 


66  OPTICAL  TRUTHS. 

hyperope  of  1.00  D,  each  eye,  has  a  4.  D.  strain.  Takdng-  one 
second  as  the  unit  of  time  measure,  4.  D.  per  second  means  240. 
D.  per  minute,  14,400  D.  per  hour  and  230,400.  D.  per  day  of 
sixteen  hours.  In  order  to  realize  fully  what  this  means  we 
must  find  out  what  the  average  demand  is  in  the  case  of  an 
ideal  person,  with  normal  eyes.  An  emmetrope,  working  at  13 
inches  for  three  hours  daily,  which  is  a  fair  average,  v/ould  use 
3.  D.  each  eye  for  accommodation  and  1.50  D.  each  for  con- 
vergence, a  total  of  9.  D.  per  second,  540.  per  minute,  32,400. 
D.  per  hour,  97,200.  D.  per  day's  work.  At  all  other  times  the 
eyes  are  practically  at  rest.  The  eyes  receive  their  supply 
from  four  and  one-third  pairs  of  nerves,  and  the  work  figured 
above  only  accounts  for  the  branches  of  the  3d  pair  which 
operate  the  ciliary  sphincters  and  the  internal  recti.  As  the 
other  branches  of  the  3d,  2d,  4th,  6th  and  the  ophthalmic 
branches  of  the  5th  have  comparatively  nothing  to  do,  and  as 
we  are  unable  to  measure  what  they  do,  we  think  it  reasonable 
to  grant  them  enough  to  make  the  above  figure  100,000,  hence 
we  charge  2.800.  D.  for  them.  Now,  as  these  four  and  one- 
third  pairs  are  36  per  cent,  of  the  entire  number  of  cranial 
nerves  and  10  per  cent,  of  the  entire  number  in  the  body,  and 
as  any  other  four  and  one-third  pairs  will  show  one  or  two 
doing  the  chief  work,  we  conclude  it  is  not  unreasonable  to 
estimate  the  proportion  throughout,  and  multiplying  100,000. 
D.  by  10  gives  a  grand  total  of  1,000,000  D.  daily  as  the  aver- 
age needs  of  the  entire  system,  hence  we  assume  that  to 
be  the  average  capacity.  Of  course  overdrafts  may  be  made 
occasionally  without  danger,  but  the  constant  drain  caused  by 

1.  D.  hyperopia  shows  a  daily  excess  demand  of  over  23  per 
cent,  and  for  the  purpose  of  easy  calculation  we  call  it  24  per 
cent.     Thus  1.50  D.  hyperopia  would  mean  36  per  cent,  excess; 

2.  D.,  48  per  cent. ;  3.  D.,  72  per  cent. ;  4.  D.,  96  per  cent.  Above 
that  there  is  comparatively  little  strain  because  the  demand  is 
so  great  there  is  little  effort,  except  for  brief  periods.  But  we 
do  find,  as  a  rule,  such  cases  are  dull  mentally,  although  quite 
hearty  physically.    When  we  know  that  hypsropic  eyes  are  the 


THE  EYES  AS  DOUBLE  GAUGES.        67 

only  organs  in  the  body  that  can  overcome  their  own  defects, 
it  is  plain  that  the  strain  must  be  a  factor  in  all  the  functional 
derangements  such  people  suffer  from.  If  they  are  astigmatic 
it  is  all  the  worse,  because  there  is  a  constant  effort  to  over- 
come that  fault  by  accommodation  and  it  cannot  be  done  be- 
cause that  effort  affects  all  meridians  alike,  the  astigmatic 
error  being  in  the  cornea  and  the  accommodation  in  the  lens. 
No  point  being  made  on  the  retina  by  the  effort,  it  is  much 
like  trying  to  climb  a  greased  pole — lots  of  work  but  little 
result.  This  is  why  astigmatism  causes  more  headaches  than 
simple  hyperopia  does.  If  the  astigmatic  error  is  as  much  as 
2.  D.  or  more,  it  causes  less  trouble  than  the  smaller  amount* 
because  vision  is  so  bad  there  is  little  attempt  to  improve  it. 

Our  critics,  referring  to  the  nerve  strain  calculation,  say: 
"According  to  your  own  figures  only  9.72  per  cent,  is  actual 
measure  and  the  rest  is  estimate."  Yes,  but  taking  the  eyes 
alone,  97.2  per  cent,  is  actual  measure  and  all  of  the  hyperopic 
strain  is  actual  measure,  while  the  estimated  part  is  applied 
equally  to  both,  so  that  by  the  law  of  ratios  the  conclusion  ia_ 
exact  and  must  yield  the  same  results  no  matter  by  what  sys- 
tem the  calculation  is  made.  The  neurometer  was  based  on 
this  calculation  and  it  works.  Our  clinical  analyses  are  based 
on  these  figures,  and  they  work. 

The  hyperope,  because  of  the  constant  activity  of  his  ac- 
commodation, develops  remarkable  strength  in  that  depart- 
ment, even  while  sacrificing  other  functions,  and  he  naturally 
notices  the  disturbance  elsewhere  before  he  does  in  his  eyes, 
because  the  extra  current  of  energy  only  makes  the  eyes  per- 
form their  functions  normally  while  other  sphincter  system* 
throughout  the  body,  which  are  normal,  receive  the  extra 
current  too,  and  it  makes  them  overdo  their  work,  with  the 
result  that  there  will  be  interference  with  the  circulation  of 
blood,  there  will  be  constipation,  bladder  troubles,  the  heart, 
stomach,  lungs  and  muscular  action  generally  will  be  insuffi- 
cient or  hypersufficient,  and  women  will  suffer  menstrual  de- 
rangements.    But  these  are  not  all.     The  supply  of  energy  in 


68  OPTICAL  TRUTHS. 

the  cerebellum  being  depleted,  there  will  be  a  deficiency  in 
the  acid  reactions  in  the  stomach  and  elsewhere,  the  blood- 
making  and  cleansing  organs  will  fail  for  chemical,  as  well 
as  mechanical  reasons,  and  then  the  whole  body  is  subject  to 
any  or  all  the  disorders  flesh  is  supposed  to  be  heir  to.  The 
abnormal  strength  of  accommodation  is  also  a  source  of  anxi- 
ety on  the  part  of  the  doctor  who  attempts  to  analyze  the  case, 
part  of  which  analysis  is  measuring  the  amount  of  hyperopia, 
hence  the  necessity  for  a  method  of  procedure  which  will  en- 
able him  to  overcome  or  circumvent  spasms,  tonic  or  clonic. 

The  need  of  such  method  is  not  limited  to  the  hyperope, 
for  the  myope  often  has  spasms  from  the  incoordination  of 
accommodation  and  convergence  at  near  points,  although  his 
nerve  strain  is  not  great  enough  to  set  up  other  functional  dis- 
turbances. A  myope  of  2.00  D.  will  rarely  read  farther  away 
than  six  or  eight  inches,  although,  theoretically,  he  should 
read  at  twenty  inches.  The  reason  is  that  when  he  holds  a 
paper  at  thirteen  inches  the  convergence  is  necessarily  1.50  D. 
in  each  eye;  this  brings  with  it  automatically  3.  D.  accommo- 
dation, which,  added  to  his  myopia  makes  his  dioptric  system 
5.  D.,  requiring  the  object  to  be  at  eight  inches.  When  he  puts 
it  there  the  eyes  must  converge  5.  D.,  or  2.50  each  and  this 
brings  5.  D.  accommodation  in  each  eye,  which,  added  to  his 
myopia  makes  7.  D.  and  puts  the  first  conjugate  focus  at  five 
and  one-half  inches.  By  this  time  his  accommodation,  which  is 
not  so  vigorous  as  the  hyperope 's,  becomes  exhausted  and  there 
is  a  harmony  of  accommodation  and  convergent  points.  But 
all  this  tends  to  make  the  accommodation  active  enough  to  fool 
any  one  who  does  not  understand  the  physics  and  physiology 
of  the  proposition.  Old  time  opticians  fitted  such  people  by 
having  them  hold  a  newspaper  as  far  from  the  face  as  they 
could  and  read  a  line,  then  measuring  the  distance  in  inches 
and  giving  the  number  corresponding.  They  wondered  why 
the  purchaser  returned  complaining,  but  weakened  the  lenses 
time  after  time  until  they  found  comfortable  ones.  If  their 
patrons  developed  stomach  trouble  and  headaches  later  they 


THE  EYES  AS  DOUBLE  GAUGES.        69 

never  thought  the  eyes  had  anything  to  do  with  it,  nor  did  the 
wearers,  who  went  to  the  doctors  for  medicine.  Later  in  life 
they  found  they  could  see  better  with  weaker  glasses  and 
could  see  at  a  greater  distance  with  their  naked  eyes,  hence 
the  idea  that  the  eyes  flatten  with  age.  This  was  corroborated, 
apparently,  by  the  fact  that  hyperopes,  who  never  wore  glasses 
for  distance  until  long  after  they  had  used  them  for  reading, 
finally  found  they  could  use  convex  glasses  to  advantage  for 
distance.  This  was  because  their  accommodation  could  no 
longer  overcome  their  defect.  Even  to-day  some  oculists  will 
insist  the  eyes  do  flatten  with  age.  There  are  also  people  who 
declare  the  earth  is  flat.  The  myope  described  above  would 
have  been  given  —  6.  to  begin  with  and  gradually  reduced  to 
—  2.50  or  3.  when  he  would  have  been  h3rperopic  .50  to  1.  and 
sufi'ering  nerve  strain,  where  before  he  only  lacked  vision. 
An  interesting  test  for  such  cases  is  to  have  a  real  myope,  or  a 
hyperope,  made  myopic  by  over-correction  with  +  5.  or  6.  D. 
spheres,  hold  a  paper  as  far  from  his  face  as  he  can  read,  then 
interpose  a  pair  of  5  or  6-degree  prisms,  bases  in,  and  note  how 
much  farther  he  can  extend  the  paper,  thus  proving  that  ac- 
commodation is  automatic  with  convergence,  because  when 
the  prisms  stop  the  necessity  for  convergence  the  accommoda- 
tion lets  go  too. 

One  of  the  infirmities  of  age  is  a  loss  of  accommodative 
power,  because  the  lens  is  held  in  suspension  and  at  its  static 
condition  by  a  lot  of  straight  ligaments  which  are  almost  over- 
come, in  early  life,  by  the  antagonism  of  the  bicycle-tire  ar- 
rangement surrounding  the  lens,  so  that  comparatively  little 
nerve  force  is  required,  but  as  this  tire  loses  its  elasticity,  from 
shrinkage  of  contents,  it  leaves  more  work  for  the  nerves  than 
they  can  do,  hence  the  need  of  glasses  for  near  work,  even  for 
emmetropic  eyes.  This  is  presbyopia.  It  is  called  total  when 
the  person  accepts  a  lens  equal  to  the  full  measure  of  the  dis- 
tance he  works ;  thus  if  +  2.50  is  accepted  for  work  at  sixteen 
inches  he  would  be  totally  presbyopic,  because  he  would  never 
need  any  stronger  glasses  for  that  distance.     This  would  be 


70 


OPTICAL  TRUTHS. 


called  total  presbyopia  even  if  he  could  read  at  eleven  inches 
with  the  same  lenses  thus  exhibiting  1.  D.  accommodation. 
An  emmetrope  sixty  years  old  would  do  that,  and  a  hyperope 
of  1.  D.  seventy  years  old  would  do  it. 


R                          " 

L^^I^ 

r^^^ — HT^^^=^  -    ■ 

J                                                                                 

— \ZT — ' 

Fig-.    49 

The  figure  (49)  shown  herewith  is  an  ideal  eye  in  the 
matter  of  dimensions.  From  the  center  of  the  lens  to  the 
posterior  pole  is  just  the  same  distance  as  that  from  the  cen- 
tre of  the  lens  to  the  line  P  in  front  of  the  eye.  This  line, 
then,  represents  the  principal  focal  plane  from  which  rays 
starting  divergent  would  pass  beyond  the  cornea  and  lens 
parallel  with  the  axis.  The  ray  R  would  be  refracted  and 
focus  at  the  posterior  pole  because  it  approaches  parallel  with 
the  axis.  Now,  while  the  eye  is  fixed  on  a  distant  object  let 
another  object  be  placed  at  farthest  point  to  the  left  shown  on 
the  axis,  which  is  just  three  inches.  The  ray  from  the  point, 
which  strikes  the  cornea  at  A  would  be  refracted  and  pass 
away  parallel  to  the  line  G  L  and  would  strike  the  axis  at  2 
if  it  could  get  there,  as  would  also  its  fellow  ray  below  the 
axis.  But  as  neither  can  get  past  the  retina,  the  circle  of 
difTusion  formed  will  have  a  diameter  equal  to  the  space  be- 
tween the  two  lines  at  the  retina.  This  shows  exactly  what 
the  circle  of  diffusion  would  be  in  a  hyperope  of  13.00  D. 
with  accommodation  at  rest. 

An  interesting  fact  in  this  connection  is  that  the  circle 
of  diffusion  from  the  distant  rays  would  be  just  as  great  if 
the  eye  was  adapted  to  the  three-inch  point.  The  same  is  true 
of  any  two  points.    To  make  it  plainer,  if  the  eyes  are  fixed 


THE  EYES  AS  DOUBLE  GAUGES.        7{ 


on  a  point,  say  thirteen  inches  distant,  rays  from  a  point  forty 
inches  away  would  form  circles  instead  of  points.  Then  re- 
verse the  proposition  and  fix  at  forty  inches;  the  rays  from 
the  thirteen-inch  point  would  form  circles  of  the  same  size. 
The  first  ones  would  focus  before  reaching  the  retina  and  the 
others  would  reach  the  retina  before  focusing.  Of  course  if 
some  critic  wants  to  split  hairs  he  would  declare  the  rays  that 
focus  before  reaching  the  retina  will  make  a  trifle  the  biggest 
circle,  but  I  will  anticipate  him  and  reply  that  he  fails  to  con- 
sider the  increased  angles  of  the  rays  from  the  nearest  point 
which  would  increase  the  dispersion  enough  to  offset  the  other. 
There  are  a  number  of  physical  problems  having  refer- 
ence to  the  eyes  that  afford  physiological  and  metaphysical 
lessons  which  more  than  repay  one  for  studjdng  them.  No 
one  in  practice  pays  enough  attention  to  the  laws  upon  which 
he  works,  whether  it  be  physician  or  tradesman. 


MEASURING  ERRORS  OF  REFRACTION. 

Cyclopleg^cs  Are  a  Humbug  Suitable  Only  to  the  Ocidists  Who 

Use  Them. 

The  emphatic  assertions  of  some  writers  with  reference 
to  the  value  of  cycloplegics  are  unwarranted  by  the  facts.  I 
assert  as  emphatically  the  drugs  are  not  only  worthless,  but 
inconvenient  and  dangerous.  I  will  tender  a  few  reasons  for 
my  claims. 

The  chief  reason  is  that  not  one  in  a  thousand  users  knows 
how  to  use  it,  as  is  proved  by  their  utter  ignorance  of  how 
to  tell  when  the  accommodation  is  paralyzed;  and  if  it  is 
incomplete  their  method  of  appljdng  lenses  could  not  possibly 
do  more  than  approximate  the  spherical  part  of  the  correction 
and  very  rarely  even  do  that  much  with  the  astigmatism, 
hence  Dr.  Gould's  assertion  that  "astigmatism  is  an  elusive 
imp  of  mischief  and  it  requires  great  keenness  and  patience 
to  hunt  him  down.  His  hiding  place  is  the  ciliary  muscle  and 
his  disguise  amblyopia.  He  hates  atropia  as  his  father  was 
said  to  hate  holy  water."  Let  one  of  the  partisans  of  atro- 
pine instill  the  drug  until  he  is  satisfied  the  accommodation 
is  at  rest,  then,  if  he  can,  let  him  fit  his  patient.  When  that 
is  done,  add  +  3.00  for  the  13-inch  point.  If  the  atropine  is 
in  absolute  control  there  will  be  no  difficulty  in  reading  ordi- 
nary print,  of  course.  Then  let  him  direct  the  patient  to  hold 
the  print  as  close  to  his  face  as  he  can  read,  measure  the  dis- 
tance in  inches,  convert  it  into  diopters  and  whatever  it 
amounts  to  over  3.00  is  the  unsuppressed  accommodation.  If 
any  demands  greater  proof  than  that  he  must  apply  to  me 
personally. 

Another  reason  is  that  anyone  who  really  knows  how  to  fit 
glasses  can  do  it  as  well,  or  better,  without  a  cycloplegic  than 
with  it,  as  will  be  shown  in  this  chapter. 

Another  is  that  when  the  drug  is  used  it  partly  disables 
one  of  our  greatest  allies  in  proving  our  work. 


74  OPTICAL   TRUTHS. 

Another  is  that  it  causes  great  inconvenience  to  the  pa- 
tient, at  least  temporarily,  and  often  permanently,  if  repeated 
too  often — a  common  fault  among  users,  who  thus  prove  they 
are  not  sure  of  their  work  from  the  results  of  one  test,  else 
repeating  it  is  dishonesty  toward  the  patient. 

Another  is  that  after  the  work  is  done  under  atropine 
they  dare  not  prescribe  the  full  correction  found  because  the 
patient  cannot  see  well;  hence  their  rule:  "Under  the  age  of 
twenty  give  one-fourth  full  correction ;  over  twenty  and  under 
thirty,  give  one-half,  and  over  thirty,  give  three-fourths  of  th^ 
full  amount. 

Another  is  that  we  want  to  show  our  patients  exactly  the 
conditions  we  are  going  to  put  them  in  at  first,  and  why,  then 
we  have  no  difficulty,  except  when  some  wiseacre  interferes, 
and  we  caution  patients  against  all  such. 

Oculists  merely  treat  eyes  (most  of  them  maltreat),  while 
ophthalmologists  use  the  eyes  to  measure  the  condition  of  the 
nervous  system  and  must,  of  course,  be  able  to  measure  their 
defects  exactly  without  creating  any  unnatural  conditions. 
For  our  convenience  and  to  facilitate  explanations,  we  classify 
the  several  cases  we  meet  into  the  folloAving: 

First — Those  with  good  vision. 

Second — Those  with  medium  vision. 

Third — Those  with  bad  vision. 

Fourth — Cross-eyes. 

Fifth — Those  with  spasm  of  accommodation. 

Sixth — Those  with  asthenopia. 

Seventh — Children  and  illiterates. 

Eighth    Old  people. 

Fig.  50  shows  the  proportions  of  the  letters  in  the  Snellen 
Test  Chart.  The  patient  being  seated  at  10,  15,  20,  30,  40,  50, 
60,  80,  120,  160  or  200  feet  from  it  should  read  the  type  corre- 
sponding to  that  distance,  as  marked  on  the  card.  The  usual 
working  distances  are  15  and  20  feet.  Visual  acuteness  is 
expressed  in  fractions,  the  numerator  being  the  distance  and 
the  denominator  the  number  of  the  type  patient  reads;  thus, 


MEASURING  ERRORS  OF  REFRACTION. 


75 


Fig-.   50 


if  seated  at  20  feet  and  number  30  type  is  the  smallest  that 
can  be  read  without  error,  vision  would  be  recorded  20/30; 
if  number  20  is  read  it  would  be  20/20,  which  equals  normal ; 
if  number  15  is  read  it  would  be  recorded  20/15.  Sometimes 
it  is  necessary  to  have  the  card  only  a  few  feet  away ;  one  eye 
may  have  20/20  vision  and  the  other  only  2/200,  that  is,  can 
only  read  the  largest  type  at  2  feet.  For  very  small  rooms 
the  15  or  20  feet  distance  may  be  obtained  by  using  a  mirror 
and  a  card  printed  backwards  so  it  will  appear  correctly  in 
the  mirror.    In  fitting  eyes  we  look  for: 

First,  -(-  spheres. 

Second,  —  cylinders. 

Third,  —  spheres. 

The  only  possible  results  are: 

First,  -|-  spheres  =  simple  hyperopia. 

Second,  4  spheres,  —  cylinders  ==  simple  hyperopic  astig- 
matism, or  compound  hyperopic  astigmatism,  or  mixed  astig- 
matism. 

-  cylinders  =  simple  myopic  astigmatism. 
—  cylinders,  —  spheres  =  compound  myopic 


Third,  - 

Fourth, 
astigmatism. 

Fifth,  —  spheres  ==  simple  myopia. 

The  second  are  the  only  ones  that  ever  need  correction 
by  transposition.  If  the  cylinder  is  weaker  than  the  sphere 
it  is  really  a  case  of  compound  hyperopic  astigmatism  and  the 
prescription  will  transpose  to  a  -f  sphere  and  +  cylinder. 
If  the  cylinder  is  of  the  same  power  as  the  sphere  it  is  a  case 


76  OPTICAL  TRUTHS. 

of  simple  hyperopic  astigmatism  and  the  formula  will  trans- 
pose to  a  simple  cylinder.  If  the  cylinder  is  the  stronger, 
ever  so  little,  it  is  a  case  of  mixed  astigmatism,  but  unless  it  is 
at  least  twice  as  strong  as  the  sphere  it  needs  transposing  to 
get  it  into  its  simplest  form. 

A  short  way  to  transpose  a  prescription  that  needs  it  is: 
Take  the  diflFerence  between  sphere  and  cylinder  for  the  new 
sphere,  then  use  the  power  of  old  cylinder,  changing  sign  and 
exis.    Thus  the  three  possible  cases  above  would  be: 
Original.  Transposition. 

-f-  1.50  —    .50  ax.  180  =  -f  1.00  +     .50  ax.  90. 
+  1.50  —  1.50  ax.     45  =  +  1.50  ax.  135. 
+  1.50  —  2.50  ax.     30  =  —  1.00  4-  2.50  ax.  1.20. 

We  proceed,  subjectively  (tests  with  retinoscopes,  refract- 
ometers,  ophthalmoscopes,  ophthalmometers,  stigmatometers, 
etc.,  are  merest  guess-work),  as  follows: 

First,  Get  the  visual  acuteness  of  each  eye,  separately,  and 
record  it.  If  it  is  normal  it  proves  there  is  no  myopia;  if  it 
is  a  line  better  than  normal  it  proves  there  is  hyperopia  of  at 
least  1.00  D.  and  that  there  is  no  astigmatism  worth  looking 
for;  if  it  is  not  as  good  as  normal  it  may  be  hyperopia  with 
insufficient  accommodation,  or  it  may  be  astigmatism,  or  it 
may  be  myopia,  or  it  may  be  the  optic  nerve  is  affected. 

Second,  Get  the  maximum  power  of  accommodation  and 
record  it.  If  the  patient's  age  is  known  and  this  is  excessive, 
it  indicates  hyperopia,  unless  there  are  no  evidences  of  nerve 
strain,  when  it  may  mean  myopia,  if  vision  was  bad  according 
to  the  first  test. 

Third,  Test  the  muscle  balance,  which  is  really  a  static 
nerve  test,  with  the  double  prism  on  one  eye,  adjusted  so 
a  light  at  fifteen  or  twenty  feet  appears  as  two,  one  above  the 
other,  and  with  a  colored  glass  on  the  fellow  eye.  The  colored 
light  should  be  in  line  with  and  midway  between  the  white 
ones.  If  it  is  ,  the  nerve  distribution  is  either  normal  or  there  is 
spasm  in  both  the  sixth  nerves  and  internal  recti  branches  of 
the  third.    In  either  case  it  is  orthophoria.    If  the  lights  are 


MEASURING  ERRORS  OF  REFRACTION. 


77 


not  in  line  it  is  heterophoria.  If  the  colored  light  deviates 
towards  the  nose'  it  is  esophoria  and  means  nervous  spasm, 
exhibited  in  the  internal  recti,  and  it  will  also  be  found  in  the 
accommodation  when  we  try  the  refraction  tests.  If  it  devi- 
ates from  the  nose  it  is  exophoria  and  signifies  weakness  of 
the  nerve  supply,  exhibited  in  the  interni  and  of  course  it  will 
be  found  in  the  accommodation  during  the  refraction  test, 
unless  it  be  a  clonic  spasm,  which  will  make  its  presence  known 
very  quickly.  If  the  deviation  is  up  or  down  in  connection 
with  either  of  the  above,  it  is  hyperesophoria  or  hyperexo- 
phoria  and  means  the  disturbance  is  more  general.  If  it  simply 
deviates  up  or  down,  it  is  hjrperphoria,  and  means  an  erratic 
distribution  of  nerve  force. 

Fourth,  Put  in  front  cell  of  trial  frame  +  spheres,  just 
strong  enough  to  blur  vision  until  the  largest  type  on  the  test 
card  is  seen  dimly,  then  put  the  next  weaker  in  the  rear  cell, 
remove  the  first  ones  and  repeat  the  operation,  using  the  next 
weaker  at  each  change  (unless  the  patient  shows  signs  of  spasm 
by  not  improving  in  vision  with  each  change,  when  it  is  proper 
to  cheat  the  accommodation  by  leaving  the  same  lenses  in 


Fig.    51 


78  OPTICAL   TRUTHS. 

while  pretending  to  change),  until  vision  is  good  enough  so 
patient  can  pick  out  a  few  letters  on  the  line  he  read  easily 
without  the  lenses.  Stop  at  this  point  and  cover  each  eye, 
alternately,  see  if  vision  is  practically  equal.  If  it  is  not,  put 
more  -f  on  the  good  eye,  then  continue  as  before  until  the 
same  point  is  reached. 

Fifth,  Direct  attention  to  the  astigmatic  chart,  Fig.  51  is 
usually  the  best,  and  require  the  patient  to  tell  which  line,  if 
any,  is  the  plainest.     If  there  is  one,  it  indicates  astigmatism 
and  that  the  meridian  at  right  angles  to  the  plainest  line  is 
the  one  corrected  by  the  sphere.     To  prove  this,  put  the  slot 
on  that  meridian  and  have  him  read  the  smallest  letters  possi- 
ble, then  reverse  the  slot  and  vision  should  be  worse.    If  it  is, 
hold  weak  —  spheres  in  front  of  the  slot,  increasing  the  power 
gradually  until  vision  is  almost  as  good  as  in  the  other  meri- 
dian; then  substitute  a  cylinder  of  the  power  indicated,  for 
the  slot,  placing  the  axis  on  the  meridian  where  the  slot  showed 
best  vision  through  the  sphere.     To  test  the  correctness  of 
the  cylinder,  first  direct  attention  to  the  astigmatic  chart  and 
let  the  patient  tell  whether  the  lines  are  all  equally  distinct. 
If  the  ones  which  were  plainest  before  are  still  most  distinct 
the  cylinder  is  not  strong  enough;  if  the  opposite  ones  are 
plainest,  it  is  too  strong.    If  he  says  they  all  appear  alike, 
reverse  the  axis,  and  if  that  spoils  the  equality  of  vision  on 
the  chart  put  its  axis  back  where  it  was,  refer  him  to  the  letters 
again  and  take  a  -(-  .25  cylinder  in  one  hand  and  a  —  .25 
cylinder  in  the  other,  then  try  them  aUernately,  the  -f-  first, 
axis  on  axis;  if  vision  is  just  as  good  with  the  -]->  the  —  cylin- 
der in  the  frame  may  be  reduced ;  if  it  is  not  as  good,  try  the 
—  cylinder,  and  if  it  improves  vision  compare  it  with  a  —  .25 
sphere,  when,  if  the  sphere  gives  best  vision,  the  original  cylin- 
der is  proved.     In  the  latter  instance  do  not  reduce  the  sphere, 
as  appears  to  be  indicated  by  the  improvement  in  vision,  but 
wait  until  the  other  eye  is  finished,  when  the  accommodation 
may  relax  a  little  more,  making  reduction  of  the  sphere  un- 
necessary.    There  are  cases  in  which  the  cylinder,  being  —  .75 


MEASURING  ERRORS  OF  REFRACTION.     79 

or  less,  may  be  stolen  without  impairing  vision  on  the  letters, 
although  the  astigmatic  chart  will  not  be  perfect.  The  man- 
ner in  which  this  is  accomplished  is  to  remove  the  cylinder 
from  the  trial  frame,  holding  it  in  one  hand  and  alternating 
it  with  a  —  .25  sphere  in  front  of  the  eye,  and  if  vision  is  best 
with  the  sphere  of  course  the  cylinder  should  be  discarded; 
or,  if  a  —  .50  sphere  gives  better  vision  than  a  —  .50  or  —  .75 

i. 
J 


Fig-.    52 

cylinder,  we  often  discard  the  cylinder.  Fig.  52  shows  the 
principle :  Let  the  plane  1  show  the  focus  of  the  vertical  meri- 
dian and  the  plane  2,  that  of  the  horizontal  meridian;  the 
plane  3  shov/s  where  the  circles  of  diffusion  would  form  a 
round  spot,  but  not  a  perfect  focus.  Suppose  the  hjrperopia 
in  the  vertical  meridian  is  1.00  D.  and  in  the  horizontal  is  1.50 
D.,  -I-  1.25  sphere  would  put  the  plane  3  at  the  retina,  the 
vertical  meridian  would  be  a  little  over-corrected  and  the  hori- 
zontal a  little  under-corrected,  but  the  saving  of  nerve  strain 
wou^'^  V-,  five-sixths  of  the  total,  and  vision  would  be  as  good 
as  with  naked  eye.  Such  corrections  are  evidences  of  skill 
and  judgment  on  the  part  of  the  operator. 

If,  in  beginning  the  test  for  astigmatism,  the  patient 
sees  no  difference  in  the  chart  Fig.  51,  it  is  not  proof  there  is 
no  astigmatism  and  the  slot  is  used  to  find  the  meridian  of  best 
vision,  when  it  is  reversed  and  the  proceeding  continued  as 
described  above. 

If,  in  proving  cylinder  reversing  the  axis  spoils  astigmatic 
chart  but  makes  letters  clearer,  there  is  not  enough  -|-  sphere. 
Increase  before  proceeding. 


80  OPTICAL  TRUTHS. 

Sixth.  After  testing  the  other  eye  for  astigmatism,  both 
eyes  are  used  to  prove  the  spherical  corrections.  Cover  the 
eyes  alternately  and  proceed  as  per  the  last  sentence  in  first 
paragraph  of  rule  four. 

Seventh.  Get  the  maximum  accommodation  with  correc- 
tion on.  If  the  patient  is  under  twenty  years  of  age  and  in 
good  condition,  it  will  not  be  any  greater  than  at  the  first  test, 
and  probably  less,  because  the  glasses  interfere  with  the  limit- 
angle  of  convergence;  if  it  is  increased,  it  means  the  patient 
needs  rest.  Between  twenty  and  thirty-five  years  the  increase 
should  approximate  the  power  of  the  -\-  spheres;  if  it  is  not 
so  much,  it  means  a  good  condition;  if  it  is  more,  it  indicates 
weakness.  If  the  age  is  over  about  thirty-five  but  the  patient 
is  not  yet  presbyopic,  the  increase  should  be  equal  to  twice 
the  strength  of  spheres ;  if  it  is  not,  it  means  general  weakness 
until  after  forty-five  years,  when  it  usually  means  presbyopia. 
If  any  patient  has  not  been  wearing  constantly  a  correction 
of  his  errors  of  refraction  and  appears  to  need  additional  sphe- 
rical power  for  close  work  under  forty-five,  do  not  give  it,  but 
require  the  correction  worn  constantly  and  rest  from  all  work 
for  a  week  or  two  when  he  will  be  able  to  do  his  close  work 
without  addition. 

Eighth.  To  find  the  proper  amount  to  add  for  close  work, 
have  patient  hold  a  newspaper  at  the  farthest  point  he  expects 
to  work,  measure  the  distance  in  inches,  take  its  equivalent 
in  diopters,  -|-  spheres,  and  offer  them,  holding  in  front  of 
both  eyes  at  once,  (be  sure  to  hold  them  in  good  position  over 
the  other  lenses) ;  if  he  cannot  read  with  them,  reduce  them 
.25  at  a  time  until  he  can  read  dimly  at  the  original  point,  then 
tell  him  to  draw  the  paper  to  the  usual  position,  when  he  will 
declare  it  perfect.  This  saves  changing  the  reading  glasses 
so  often  and  insures  best  results  from  the  lenses.  If,  as  will 
be  found  occasionally,  in  cases  where  the  hyperopia  is  so  great 
that  vision  is  poor  even  with  best  correction  obtainable  by  the 
distance  test,  the  patient  requires  an  addition  for  reading  of 
greater  amount  than  the  working  distance  represents,  increase 


MEASURING  ERRORS  OF  REFRACTION.     St 

the  lenses  for  constant  wear  the  amount  of  that  difference. 
For  example,  a  patient  accepts  +  6.00  for  distance,  but  for 
reading  at  13  inches  +  4.00  must  be  added ;  it  follows  that  as 
only  -f  3.00  is  required  by  law  the  other  +  1.00  must  be  added 
to  the  lenses  for  constant  wear ;  they  will  be  accepted  readily, 
too. 

Ninth.  Test  the  muscle  balance  as  before ;  the  cylinders 
may  be  removed  for  this  purpose  because  they  are  always  — , 
but  the  spheres  must  remain.  If  the  frame  has  three  cells  it 
is  not  necessary  to  remove  the  cylinders.  If  there  was 
esophoria  before  and  it  remains  to  the  extent  of  V  to  3°,  we 
know  there  is  still  .50  hyperopia  concealed  by  a  tonic  spasm; 
if  there  is  4^  to  6°,  .75  hyperopia  is  concealed;  if  it  is  7°  to  10°, 
there  is  1.00;  if  it  is  11°  to  13°,  there  is  1.50,  and  if  it  is  14°  or 
more  there  is  2.00  D.  concealed,  and  we  add  these  respective 
amounts  to  the  correction  accepted,  regardless  of  vision,  be- 
cause constant  wear  will  cause  natural  relaxation,  and  when 
the  spasm  is  broken  we  retest  and  make  whatever  changes 
may  be  found  necessary  to  be  exact.  In  many  cases  we  are 
able  to  prove  the  correction  at  once  by  the  use  of  the  neuro- 
meter.  For  example,  a  patient  accepted  +  2.00  with  20/20 
vision,  showed  an  accommodation  of  9.00  D.,  indicating  23 
years,  4  months,  by  the  neurometer;  he  showed  esophoria  of 
2°  by  this  test,  so  -f  .50  was  added  arbitrarily.  Reference 
to  the  neurometer  table  of  additions  to  age  for  hyperopia  indi- 
cated 4  years,  making  27  years,  4  months;  then  for  his  pro- 
fessional work,  which  develops  the  intellectual  brain  and 
makes  the  nervous  system  more  responsive  to  demands,  there 
was  added  7  years,  6  months,  making  a  grand  total  of  34 
years,  10  months.  He  said  he  was  35  years,  3  months  and  5 
days.  By  changing  our  correction  to  +  1.75  he  saw  20/20 
well ;  adding  the  +  .50  for  esophoria,  made  +  2.25,  for  which 
the  table  says  add  4  years,  5  months,  10  days  to  the  showing  by 
accommodation  and  profession.  Thus  23  years,  4  months,  plus 
7  years,  6  months,  plus  4  years,  5  months,  10  days,  equals  35 
years,  3  months,  10  days,  and  we  decide  to  prescribe  +  2.25 


82 


OPTICAL   TRUTHS. 


instead  of  +  2.50,  which  proved  correct  by  later  tests  after 
his  nervous  irritation  subsided. 

Tenth.  Nearly  all  cases  should  wear  spectacles,  at  least 
until  the  nervous  system  recovers  its  normal  status;  it  is 
essential  for  appearance  as  well  as  comfort  that  the  measure- 
ments be  taken  properly  and  the  prescription  filled  as  written. 
A  common  fault  among  manufacturing'  opticians  is  they  do 
not  exhibit  ordinary  intelligence,  or  honesty,  in  their  work; 
they  take  a  pair  of  pliers  and  bend  a  nose-piece  until  it  corre- 
sponds to  the  measures  given,  with  the  result  that  the  patient 
looks  like  a  caricature  when  he  puts  it  on.  They  call  this 
"prescription"  work,  which  is  a  mistake. 

A  « 


Fig.    5c 


Fig.  53  shows  what  is  called  a  "saddle"  bridge,  or  nose- 
piece,  by  opticians.  The  shanks  extending  fron\  1  and  2  to 
the  lenses  are  for  the  purpose  of  changing  the  pupillary  dis- 
tances with  a  simple  twist  of  the  wrist;  it  is  a  convenient 
thing  for  the  mechanic,  and  is  not  always  hideous  in  its  results 
because  some  noses  require  little  or  no  change  and  it  does 
fairly  well,  but  there  are  a  great  many  cases  where  the  bend 
for  the  shank  should  be  just  where  the  temples  cross  the  bridge 
in  Fig.  53,  and  the  spectacles  shown  in  the  cut  would  look 
neater  on  any  face.  They  should  be  made  "saddle,"  but 
more  like  the  old-fashioned  "C"  bridge.  Hoping  that  this 
may  come  to  the  notice  of  opticians,  I  suggest  they  adopt  the 


MEASURING  ERRORS  OF  REFRACTION. 


83 


idea  when  a  prescription  comes  with  the  injunction,  "Make 
this  bridge  of  as  little  material  as  possible."  The  intent  of 
the  saddle  is  to  permit  the  operator  to  adjust  a  trifle  if  neces- 
sary. The  optician  should  make  frames  to  the  measures,  not 
bend  to  them. 

The  following  measurements  are  all  that  are  necessary: 
Distance  between  pupils,  X  to  X,  in  Fig.  53,  (to  find  it  exactly 
in  a  pair  of  glasses,  measure  from  A  to  B,  in  the  cut),  height 
of  bridge  from  where  temples  cross,  as  shown  in  cut,  to  inside 
of  top;  width  of  bridge  at  base,  1  to  2  in  the  cut;  position  of 
crest  or  top  of  bridge  with  reference  to  a  plane  corresponding 
to  the  side  of  the  lenses  nearest  the  face;  sometimes  it  is  on 
the  plane,  sometimes  back  of  it,  and  sometimes  in  front,  the 
latter  most  rarely,  the  object  being  to  regulate  the  distance 
of  the  glasses  from  the  eyelashes.  The  angle  of  the 
crest  of  the  nose  will  take  care  of  itself  if  the  optician 
follows  my  suggestion  with  reference  to  the  shanks;  it  is  a 
law  of  nature,  (as  absolute  as  is  the  law  of  nonspherical  curva- 
tures, that  the  two  principal  meridians  are  always  at  right 
angles  to  each  other).  The  temple  distance  is  not  measured, 
but  is  regulated  by  the  size  of  the  lenses.  A  very  small  face 
would  require  1-eye  lenses,  while  a  very  broad  one  would  need 
0000-eye.  The  length  of  the  hook  temples  should  be  given, 
and  make  them  so  long  that  the  ends  are  just  concealed  by 
the  lower  part  of  the  ears  as  the  observer  stands  in  front. 
Great  discomfort  results  from  making  them  too  short. 

Have  a  set  of  frames  as  follows  for  convenience  in  fitting : 


NOSE. 


Size  of  Eye.    P.  D.    High.    Wide. 


Crest. 


Temples. 


I 

2% 

i-i6 

y2 

I -16  Back 

Short 

o 

2V^ 

% 

9-16 

On  plane 

Med. 

o 

2  5-i6 

3-i6 

H 

On  plane 

Long 

o 

2  3/^ 

% 

5/8 

On  plane 

Long 

o 

2  3/^ 

% 

H 

Yi  Back 

Long 

oo 

2^ 

i/i6 

'A 

Ys  Back 

Long 

84  OPTICAL   TRUTHS. 

If  skeleton  lenses  are  wanted,  order  a  size  larger  than  the 
fitting  frame. 

If  eye-glasses  are  wanted,  they  should  be  of  the  same  size 
as  the  fitting  frame. 

The  foregoing  applies  to  the  first  and  second  classes  enu- 
merated at  the  beginning  of  this  chapter,  except  that  for  the 
second  class  it  is  usually  best  to  take  each  eye  separately  all 
the  way,  except  in  the  final  proving  of  the  spheres.  In  doing 
this  unfog  with  —  spheres  .25  and  .50;  then  .50  and  .75;  then 
.75  and  1.00,  etc. 

The  third  class  is  seldom  difficult  if  there  is  any  vision 
at  twenty  feet.  If  there  is  not,  move  patient  closer  until  two 
or  three  lines  of  the  test  type  are  visible,  then  try  the  pin- 
hole disk  and  if  it  improves  vision  there  is  just  that  much 
encouragement.  Next  try  the  slot,  whether  the  pin-hole  im- 
proves or  not.  If  one  meridian  is  better  than  the  other,  leare 
the  slot  there  and  put  such  strong  -j-  spheres  in  the  rear  cell 
that  they  make  vision  worse,  then  neutralize  gradually  with 
—  .25,  —  .50,  etc.,  until  the  vision  is  as  good  as  it  was  through 
the  slot  without  the  lens.  Put  in  the  +  spheres  indicated,  if 
any  has  been  accepted,  then  reverse  the  slot  and  vision  should 
be  worse.  First  offer  -f  spheres  in  front  of  the  slot  and  if 
they  are  accepted,  with  improvement  of  vision,  continue  in- 
creasing until  the  best  possible  \ision  is  obtained,  then  give 
enough  more  to  blur  to  the  top  line  and  neutralize  away  as 
before.  If  +  spheres  are  not  accepted,  try  — ,  and  when  that 
meridian  sees  as  good  as  the  other,  stop  and  put  on  the  cylin- 
der indicated,  prove  it  and  proceed  to  get  vision  as  good  as 
possible  by  weakening  the  4-  sphere  if  necessary.  In  other 
words,  find  the  best  meridian  if  there  be  one,  which  locates  the 
two  principal  meridians.  Use  the  slot  to  isolate  all  but  one 
at  a  time  and  treat  it  as  simple  hyperopia  or  myopia.  Then 
put  the  results  on  a  cross,  diagram  them  and  write  the  pre- 
scription, put  it  on  the  patient  and  prove  it. 

The  fourth  class  is  so  important  in  many  respects  that  a 
chapter  has  been  devoted  to  it,  which  see. 


MEASURING  ERRORS  OF  REFRACTION. 


85 


The  fifth  and  sixth  classes  need  temporary  sphericals.  The 
fifth  should  be  fogged  to  20/80  as  a  rule,  until  the  spasm 
breaks  down,  while  the  method  described  in  connection  with 
Fig.  51  is  best  for  the  sixth. 

The  seventh  class  children  can  often  read  the  letters  and 
is  comparatively  easy,  except  that  nearly  all  have  a  clonic 
spasm  of  accommodation  and  must  be  handled  carefully. 
Illiterates  are  comparatively  easily  handled  by  using  the  clock- 
face  chart,  fogging  at  twenty  feet  until  the  chart  blurs,  then 
unfogging  until  it  is  clear.  If  there  is  astigmatism  so  that 
patient  sees  one  line  plainest,  fog  and  unfog  until  the  opposite 
line  appears  plainest,  then  put  in  the  -(-  sphere  indicated  and 
finish  with  —  cylinders,  axis  opposite  the  black'  lines.  Unless 
there  is  much  astigmatism  do  not  correct  it.  If  addition  for 
reading  is  necessary,  let  patient  be  the  judge  of  what  is  best. 

For  the  eight  class  permit  20/20  vision  with  distance 
glasses,  and  add  all  the  spheres  they  will  accept  for  the  near 
work.  Remember  in  adding  for  reading  the  cylinder  is  not 
changed.     Increasing  the  sphere  gives  what  the  eye  needs. 

It  is  not  unusual  to  find  people  wearing  glasses  with  the 
axes  of  cylinders  at  oblique  meridians,  when  they  should  not 
be  so.  This  is  because  they  were  fitted  by  novices  or  dog- 
matists who  did  not  know  the  first  principles  of  anatomy  and 
physiology,  physics  or  practice. 

9^  ffi 


*^^"3225:x?^ 


p  Fig.   64  L 

Fig.  54  shows  a  case  in  which  there  is  irritation  of  the 
general  nervous  system  to  the  spasm  stage.    It  is  exhibiting  in 


85 


OPTICAL  TRUTHS. 


the  third  nerves'  branches  to  the  inferior  oblique  muscles  of 
both  eyes,  with  the  result  that  they  pull  enough  to  rotate 
the  eyes  fifteen  or  twenty  degrees  or  more,  so  that  the  two 
first  principal  meridians,  yO  and  180,  and  the  two  second  prin- 
cipal meridians,  45  and  136,  are  moved  to  the  dotted  lines, 
and  the  operator,  believing  it  was  true  oblique  astigmatism, 
fitted  the  cylinders  to  those  meridians.  The  spasm  is  also 
present  in  the  other  branches  of  the  third  nerves  which  oper- 
ate the  lenses  and  much  of  the  hyperopia  is  concealed.  In  such 
cases  I  have  found  invariably  that  not  over  one-half  of  the 
hyperopia  was  corrected.  It  is  often  possible  to  take  these 
and,  while  the  axes  are  found  oblique  when  correcting  each 
eye  separately,  to  shift  both  to  90  or  180  or  to  the  second 
principal  meridians  at  the  moment  of  permitting  binocular 
vision,  thus  securing  comfort  and  settling  the  question  at  once ; 
but  as  a  rule  it  is  better  to  prescribe  temporary  spheres  until 
the  nerve  supply  measures  o.  k,,  then  it  will  be  discovered  the 
obliquity  has  disappeared. 

I 


iV-^^ 


Fig.   55 

The  same  is  true  of  the  reverse  condition  as  shown  by  Fig. 
55,  when  the  stage  of  collapse  is  reached  and  the  nerve  sup- 
ply being  weak  allows  the  inferior  oblique  to  slack  up  too 
much.  These  cases  are  easier  to  control  than  the  first  class, 
but  caution  is  always  the  better  part  in  doubtful  cases. 


THE  NEUEOMETER. 

Method  by  Which  We  Prove  the  Accuracy  of  Our  Analyses. 
One  of  the  best  ways  to  study  a  subject  is  to  fix  an  ideal, 
then  compare  the  real  with  it  and  keep  statistics.  This  is  the 
method  I  practiced  in  constructing  the  Neurometer  (nerve 
measure).  Prof.  Bonders  printed,  many  years  ago,  the  follow- 
ing table  of  accommodation,  to  show  hov/  it  weakens  from 
youth  to  old  age  and  used  it  as  a  basis  of  calculation  for  the 
power  of  glasses  for  presbyopia. 

10  years,  14.00  D. 

20  years,  10.00  D. 

30  years,     7.00  D. 

40  years,     4.50  D. 

50  years,     2.50  D. 

60  years,  1.00  D. 
He  claimed  that  after  40  years,  wiien  the  person  with  4.50 
D.  accommodation,  or  less,  used  3.00  D.  for  reading  at  13  inches 
it  took  so  nearly  all  that  the  eyes  soon  tired.  Of  course,  it  was 
the  nerve  supply  in  the  cerebellum  that  gave  out,  but  it  exhi- 
bited in  the  eyes,  so  he  was  partly  right ;  but  he  was  mistaken 
in  another  important  particular ;  he  often  prescribed  more  than 
-f  3.00  for  work  at  13  inches  and  because  the  patient  could 
see  distant  objects  perfectly  without  glasses  he  assumed  there 
was  emmetropia,  hence  his  table  of  numbers  for  glasses  to  be 
used  at  different  ages  in  presbyopia  is  wrong,  for  any  eye 
that  is  emmetropic  will  focus  parallel  rays  at  the  retina  with- 
out accommodation,  hence  would  never  need  more  than  4- 
3.00  for  13  inches.  Or,  an  ametrope,  with  exact  correction, 
will  never  need  more  than  -f  3.00  added  for  work  at  13  inches. 
He  will  not  need  all  of  that  when  he  begins  to  require  addi- 
tion for  reading,  as  he  will  be  able  to  do  some  of  the  work 
for  a  long  time. 

However,  the  professor's  table  gave  me  an  idea  for  which 


88  OPTICAL   TRUTHS. 

I  am  duly  thankful,  and  I  elaborated  it  into  an  ideal  standard 
for  ideal  persons  with  ideal  eyes.  It  is  assumed  that  the  ideal 
day's  near  work  amounts  to  three  hours'  actual  application 
at  about  13  inches.  On  applying  this  standard  to  several 
hundreds  of  cases  I  found  many  persons  work  more  than  three 
hours  at  close  work,  and  such  were  invariably  older  than  the 
table  indicated  for  their  accommodation,  so  I  made  allowances 
for  the  extra  development  from  the  extra  work  as  will  be  seen. 
Then  I  found  that  hyperopes,  whose  accommodation  is  con- 
stantly at  work  during  waking  hours,  also  showed  over- 
developed power  in  the  eye  department,  even  v/hen  they  exli:.- 
bited  weakness  in  other  parts  of  the  body.  This  necessitated 
more  allowances,  not  only  for  the  hyperopia,  but  for  extra 
hours'  work  at  near  points  and  for  the  effects  of  the  extraor- 
dinary demands  upon  the  nerve  supply  as  found  by  examina- 
tions and  tests,  all  of  which  follow  and  have  been  proved 
abundantly  by  myself  and  my  pupils,  who  understand  my 
methods  of  taking  measurements. 

For  the  dynamic  test  we  use  the  ordinary  type  in  vogue 
with  the  daily  newspapers  of  our  time,  have  the  patient  read 
aloud,  holding  the  paper  as  near  as  possible  to  read  a  line  by 
straining.  We  measure  the  distance  from  paper  to  the  prin- 
cipal plane  of  the  eye,  which  is  at  the  apex  of  the  cornea,  and 
express  the  amount  in  dioptres. 

For  the  static  test  we  use  a  double  prism  before  one  eye 
and  a  red  glass  before  the  other;  it  makes  no  difference  which 
eye  the  red  glass  is  on,  but  I  put  it  before  the  eye  nearest  to  me. 
The  three  lights  should  be  in  a  vertical  line,  the  red,  of  course, 
in  the  middle.  If  the  red  deviates  toward  the  patient's  nose 
it  indicates  a  +  impulse,  that  is,  an  irritation  of  the  nervous 
system  to  such  an  extent  that  it  is  in  a  state  of  tonic  spasm 
throughout  the  body.  We  know  by  this  there  is  not  only 
hyperopia  but  that  the  spasm  of  accommodation  is  so  great 
we  will  have  a  fight  to  control  it,  and,  after  we  have  made 
the  refraction  test  and  got  on  all  the  +  we  can,  if  the  static 
test  repeated  shows  the  +  impulse  remaining  we  have  proof 


THE  NEUROMETER.  89 

we  did  not  get  all  the  hyperopia — the  neurometer  tells  how 
much  is  lacking-.  If  the  red  light  deviates  from  the  nose  it  indi- 
cates a  —  impulse,  or  exhaustion  of  the  nerve  supply  to  such 
an  extent  that  as  soon  as  the  eyes  are  throv/n  out  of  gear 
(which  is  practically  what  the  test  does),  it  exposes  the  truth 
even  if  the  dynamic  test  deceived  us.  We  know  then,  that 
there  will  not  be  a  great  deal  of  resistance  during  the  refrac- 
tion test,  although  we  are  equally  as  vigilant  as  when  dealing 
with  a  state  of  irritation;  and  if  the  static  test,  applied  after 
correction  shows  some  deviation  or  none,  the  neurometer  tells 
what  it  means  and  what  to  do.  If  the  red  light  deviates 
tov/ard  or  from  the  nose  and  above  or  below  the  mid-line  be- 
tween the  white  lights,  it  indicates  an  erratic  nerve  distribu- 
tion as  well  as  the  -|-  or  —  impulse ;  or,  if  the  red  deviates  up 
or  down,  but  neither  to  right  or  left,  it  indicates  an  erratic 
state  of  the  nerves,  either  clonic  or  tonic  spasm.  The  static 
test  is  of  no  use  on  one-eyed  or  cross-eyed  people. 

Four  points  are  worthy  of  especial  mention  in  this  con- 
nection: First,  our  -|-  impulse  is  esophoria,  that  is  the  eyes 
tend  inward  from  spasm  of  the  nerve  supply,  exhibited  through 
the  internal  recti  muscles  of  not  one  but  both  eyes.  My  oppo- 
nents, who  claim  the  eyes  deviate  opposite  to  the  direction 
the  lights  are  seen,  call  it  exophoria,  meaning  eyes  turning 
outward.  Second,  our  —  impulse  is  exophoria,  eyes  tending 
outward  from  weakness  of  the  nerve  supply  exhibited  through 
the  internal  recti  muscles.  My  opponents  call  this  esophoria 
by  the  same  token  they  call  the  other  exophoria.  They  also 
declare  the  eyes  turn  in  from  weakness  of  the  external  recti 
muscles  and  turn  out  from  weakness  of  the  intemi.  Third, 
they  say  muscles  are  at  fault  when  there  is  deviation  with 
the  test  on,  even  if  the  patient  controls  the  two  eyes  and  holds 
them  in  perfect  balance  with  the  test  off,  which  is  nearly 
always  the  case.  I  say  it  is  the  nerve  supply  away  back  in  the 
cerebellum  which  is  at  fault.  They  operate  and  if  the  nerve 
supply  is  suflBcient  to  overcome  the  damage,  they  claim  a  vic- 
tory for  operation;  if  the  nerve  supply  is  insufficient  to  act 


90 


OPTICAL  TRUTHS. 


properly,  in  spite  of  the  operation,  they  admit  no  blame,  bnt 
the  victim  has  troubles  galore.  I  never  operate  and  always 
have  good  results.  Fourth,  the  amount  of  prism  required  to 
set  the  red  light  in  the  middle  is  not  the  measure  of  the  de- 
grees of  deviation,  but  is  an  indication  of  the  intensity  of  the 
spasm  if  prism  required  is  base  in,  or  of  the  extent  of  the  ex- 
haustion if  it  is  base  out.  The  prisms  are  merely  artificial 
substitutes  for  the  natural  impulse  which  is  supplied  under 
the  direction  of  the  controlling  center  in  the  brain,  when  the 
test  is  ofi.  I  would  give  a  patient  half  a  dozen  grains  of 
strychnine  as  quickly  as  I  would  a  prism  for  constant  wear. 
See  chapter  on  prisms. 

THE  NEUROMETEE. 

Age. 


Near 

Point. 

2% 
3 

in 

31/4 
31/2 
4 

c  c 

41/2 
434 

5 

i  i 
i  t 
i  i 

51/4 
51/2 
5% 
6 

i  i 
i  < 

C  i 

61/4 
61/2 

6% 

n 
1 

i  I 

71/2 
8 

i  ( 
it 

8I/2 
9 

91/2 

( i 

Diopters. 
..14.00.. 
..13.00.. 
..12.00.. 
..11.00.. 
..10.00.. 
.  .  9.00.  . 
.  .  8.50.  . 
.  .  8.00.. 
. .  7.50.. 
.  .  7.00.. 
. .  6.75.. 
.  .  6.50.. 
.  .  6.25.. 
. .  6.00.. 
..  5.75.. 
..  5.50.. 
..  5.25.. 
..  5.00.. 
..  4.75.. 
..  4.50.. 
..  4.25.. 


Years 

..10 

..12 

..15 

..17 

..20 

..23 

..25 

..26 

...28 

...30 

...31 

...32 

...33 

...34 

...35 

...36 

...37 

...38 

...39 

...40 

...41 


"s.         Months. 
0 

Days. 
.. .0. . 

6 

. ..0. . 

0 

. . .0. . 

6 

0.  . 

0 

0.  . 

4 

.. ..0. . 

0 

0.  . 

8 

0.  . 

4 

....0.. 

0 

0.. 

0 

0.  . 

0 

....0.. 

0 

....0.. 

.      . . .0 

0.  . 

,     0 

0.  . 

1 0 

....0.. 

'     0 

....0.. 

5 0 

....0.. 

)           ,    ..0 

0.. 

)           0 

....0.. 

L 3 

....0.. 

THE  NEUROMETER. 


91 


4.00.... 

42. 

3.75.... 

43 

3.50.... 

45 

3.25.... 

46 

3.00.... 

47 

..: 2.75.... 

48 

2.63.... 

49 

2.50.  ... 

50 

2.25.... 

51 

2.00.... 

53 

1.75.... 

55 

1.50.... 

56 

1.25.... 

58 

1.00.... 

60 

6 

0.. 

9 

0.  . 

0 

0.. 

3 

0.. 

6 

0.  . 

9 

0.  . 

4.... 

0 

....15.. 

0.. 

8 

0.  . 

4 

0.  . 

0 

0.. 

.  .8 

0.  . 

4 

0.. 

) 0.  .  .. 

.....o.. 

10 

lOl/o 

11 

12 

13 
14 
15 
16 
18 
20 
22 
26 
32 
40 

If  our  patient  is  an  emmetrope  but  works  extra  hours  over 
the  average  three  upon  which  this  table  is  based,  we  would  add 
to  his  showing  by  the  dynamic  test: 

For  6  hours  extra,  10  years,  0  months. 
For  5  hours  extra,    8  years,  4  months. 
6  years,  8  months. 
5  years,  0  months, 
3  years,  4  months. 
1  year,    8  months. 
If  the  patient  is  a  hyperope  and  is  working  extra  hours, 
too,  it  is  evidently  just  that  much  worse  for  him,  so  we  figure 
the  extra  hours  equal  to  more  error,  thus: 

6  hours  extra  equals  1.00  D.  more  hyperopia. 
5  hours  extra  equals,    .75  D. 
.75  D. 
.50  D. 
50  D. 

.25  D.  more  hyperopia. 
For  intelligent  people  who  apply  themselves  diligently, 
thinking  and  reading,  we  add  from  5  to  10  years  for  the  men- 
tality and  its  effect  on  the  accommodation. 

All  calculations  where  errors  of  refraction    exist    must 


For  4  hours  extra. 
For  3  hours  extra. 
For  2  hours  extra, 
For  1  hour    extra, 


4  hours  extra  equals 
3  hours  extra  equals 
2  hours  extra  equals 
1  hour    extra  equals 


more  hyperopia, 
more  hyperopia, 
more  hyperopia, 
more  hyperopia. 


92 


OPTICAL   TRUTHS. 


include  the  following-  table  with  variations,  unless  especially 
exempted: 

ADDITIONS  FOR  HYPEROPIA. 
For  1.00  D.  add  10 0 


For     .75  or  1.25 

For     .50  or  1.50 

For  1.75 

For  2.00 

For  2.25 

For  2.50 

For  2.75 

For  3.00 

For  3.25 

For  3.50 

For  4.00 

For  4.50 

For  5.00 


0 
0 
0 
.0 
0 
0 
0 
0 
0 

20 

10 

0 

0 

0 


This  table  is  subject  to  alterations  for  conditions  found  by 
the  examinations  and  tests: 

First,  if  the  static  test,  without  glasses,  showed  a  -f-  im- 
pulse and  it  remained  after  the  correction  of  the  errors  of 
refraction,  we  would  increase  the  spherical  part  of  the  correc- 
tion 4-  .50  for  1  to  3  degrees,  increase  the  spherical  part  of 
the  correction  -|-  .75  for  4  to  6  degrees,  increase  the  spherical 
part  of  the  correction  +  1.00  for  7  to  10  degrees,  increase  the 
spherical  part  of  the  correction  -|-  1.50  for  11  to  13  degrees, 
increase  the  spherical  part  of  the  correction  -\-  2.00  for  14  to 
18  degrees,  regardless  of  the  vision,  because  the  showing  indi- 
cates spasms  of  the  nervous  system  which  are  concealing 
approximately  that  amount  of  hyperopia,  as  the  results  after 
wearing  constantly  for  a  few  weeks  will  show. 

Second,  if  the  static  test,  with  correcting  glasses  on, 
showed  a  —  impulse,  we  would  not  add  as  much  to  the  age 
for  the  error  as  if  there  were  no  symptoms  of  breaking  down 
in  the  nervous  system: 

For  2  to    4  degrees  we  would  deduct  25  per  cent. 


THE  NEUEOMETER.  93 

For  5  to    8  degrees  we  would  deduct  50  per  cen*. 

For  9  to  12  degrees  we  would  deduct  75  per  cent. 

Then  there  are  other  things  to  make  allowance  for,  such 
as  partial  presbyopia,  previous  corrections  of  errors  of  refrac- 
tion, —  or  partial  corrections,  and  other  features  of  the  case 
not  exhibited  by  the  static  test  but  by  the  patient's  story, 
by  the  ophthalmoscope,  by  the  general  appearance,  etc.  Some- 
times there  is  not  enough  in  one  symptom  to  warrant  much 
allowance,  but  the  total  showing  does,  so  we  make  it  that  way. 
This  -is  a  point  which  is  difficult  to  make  clear  except  by  per- 
sonal instruction,  over  clinics.  However,  the  bright  student 
will  catch  the  idea  and  soon  work  it  out  himself. 

As  a  safe  and  simple  basis  to  work  on,  we  take  the 
dynamic  test,  with  the  correction  of  errors  of  refraction,  and 
add  to  its  showing  the  amount  indicated  for  the  hyperopia 
(we  make  no  addition  if  there  is  myopia),  then  if  the  patient 
is  younger  than  he  figures,  his  condition  is  below  the  standard 
of  the  class  to  which  he  belongs;  and  if  he  is  more  than  half 
way  to  the  showing  by  the  first  table  he  is  below  the  danger- 
line.  Any  person  who  is  younger  than  the  first  table  indi- 
cates is  practically  dead  and  will  need  the  undertaker  very 
soon. 

For  example,  a  patient  requires  a  correction  for  hyperopia 
of  1.50  and,  with  that  correction  on,  shows,  by  the  dynamic 
test,  8.00  D;  we  refer  to  the  first  table  and  find  the  age  26 
years,  8  months,  and  adding  7  years,  6  months,  for  the  error, 
as  required  by  the  other  table,  gives  34  years,  2  months,  as  the 
standard  of  his  class;  if  his  real  age  is  below  that  he  is  on 
the  down  grade ;  if  it  is  more  than  half  way  down  to  26  years, 
8  months,  he  is  below  the  danger  line;  if -he  is  below  the  lowest 
age  given  it  is  a  hopeless  case. 

The  whole  object  in  figuring  out  the  ages  without  the  aid 
of  the  patient  is  to  place  the  true  value  on  the  symptoms  found 
and  to  prove  to  ourselves  and  the  patient  the  accuracy  of  our 
system  of  analysis. 

The  relation  between  the  dynamic  and  static  tests  and  the 


94  OPTICAL   TRUTHS. 

correction  of  errors  of  refraction  affords  a  nice  little  lesson 
in  delicacy  of  work:  First,  the  dynamic  test  being  voluntary, 
the  patient  is  liable  to  deceive  us,  so  the  static  or  involuntary 
test  follows  and  if  they  dispute  each  other  we  believe  the 
static,  because  all  positive  impulses  induced  by  the  defects 
in  the  eyes  are  removed,  except  when  there  is  tonic  spasm; 
even  then  we  have  either  the  positive  exhibit  by  the  static 
test  or  there  will  be  so  much  pain  in  the  eyeballs  that  we  are 
not  in  doubt.  Second,  the  dynamic  and  static  tests,  with  the 
subordinate  ones  are  constant  checks  on  each  other.  Third, 
in  persons  under  20  years  we  expect  to  find  great  power  by 
the  dynamic  test  whether  they  are  a  little  weak  or  not,  but  if 
the  djmamic  test  with  the  correction  on  shows  more  power  than 
it  did  before,  we  have  proof  of  weakness  sufficient  to  require 
absolute  rest  as  a  part  of  the  treatment,  because  the  near-point 
of  convergence  is  so  close  to  the  face  that  the  limit-angle  is 
reached  at  the  first  test.  We  add  the  power  of  the  lens  to  the 
showing  by  the  first  test  to  get  the  full  dynamic  power  because 
the  patient  must  have  been  accommodating  just  the  amount  of 
the  hyperopia  more  than  he  showed  at  the  first  test.  Between 
20  and  35  the  djuamic  test  should  show  exactly  as  much  more 
power  with  the  correction  on  than  before,  as  the  lens  repre- 
sents; if  he  shows  less,  there  is  either  a  mistake  in  the  test 
or  he  is  in  excellent  condition — which  we  would  usually  be 
inclined  to  doubt  from  the  fact  that  he  came  for  help — but  if 
he  shows  a  greater  increase  than  the  lens  amounts  to  it  is 
proof  that  he  is  in  a  weak  condition.  After  35  until  presby- 
opia begins,  the  dynamic  test  should  show  an  increase  with 
correction  on  equal  to  at  least  twice  the  strength  of  the  lens 
used;  if  he  does  not,  it  is  either  weakness  from  causes  requir- 
ing rest  as  a  part  of  the  treatment  or  from  presbyopia,  and  we 
are  able  to  tell  which  it  is  by  the  general  showing.  No  one 
under  45  should  be  presbyopic  and  if  we  find  one  we  always 
order  rest  until  he  recuperates,  when  he  will  not  need  reading 
glasses  if  he  will  wear  his  correction  constantly — and  if  he 
does  not  he  will  wish  he  had  when  the  consequences  arrive. 


THE  NEUROMETER.  95 

He  Avill  not  be  able  to  secure  comfort  with  any  glasses.  After 
50  presbyopia  comes  gradually,  requiring  occasional  changes 
of  the  reading  portion  of  the  glasses,  until  the  full  dioptric 
number  for  the  working  distance  is  accepted,  when  no  more 
changes  will  be  necessary.  After  this  point  is  reached  the 
dynamic  test  will  not  work  until,  after  completing  the  correc- 
tion of  the  errors  of  refraction  and  adding  +  3.00  for  reading, 
wo  require  the  patient  to  hold  the  paper  as  near  to  his  face 
as  he  can  read  a  line,  take  the  measure  in  inches,  express  it  in 
diopters,  just  as  in  all  other  cases,  but  we  must  deduct  the  3.00 
we  supplied ;  the  remainder  will  be  the  showing  by  the  dynamic 
tesli,  and  we  get  his  age  from  the  first  table,  adding 
nothing  for  his  error,  unless  he  has  worn  a  correction  many 
years;  and  even  then  we  would  be  more  liable  to  add  some- 
thing for  his  intelligence  and  education  than  for  any  other 
reason.  Fourth,  in  beginning  an  examination,  when  we  try 
the  dynamic  test,  if  the  patient  shows  the  power  of  a  younger 
person,  according  to  the  first  table,  we  diagnose  hyperopia 
and  a  vigorous  nervous  system;  but  if  the  static  test,  which 
follows,  shows  a  —  impulse,  it  tells  us  the  nerve  demand  has 
weakened  the  supply,  and,  at  worst,  we  will  only  have  to  con. 
tend  with  a  clonic  spasm ;  if  the  static  test  shows  nothing  there 
may  be  either  tonic  spasm  or  neurasthenia  and  only  the  com- 
plete examination  will  settle  the  question;  it  is  very  rarely, 
however,  that  the  dynamic  and  static  tests  fail  to  tell  their 
stories,  and  as  I  have  said,  the  other  tests  tell  which  is  right 
when  they  differ;  I  may  add  that  when  they  do  fail  we  still 
have  the  others  to  help  us. 

The  neurometer  is  not  only  an  invaluable  aid  in  analyzing 
the  condition  of  the  nerve  supply  but  by  it  we  are  able  to 
ascertain  the  seat  of  the  primary  cause  with  reference  to 
whether  it  is  mental  or  physical  or  both. 

Case  1.  G.  A.  M. ;  a  Swede;  mechanic;  neurotic  temper- 
ament ;  height,  5  ft.,  9  in. ;  weight,  130  lbs. ;  history  of  malnu- 
trition as  child ;  varicocele  since  seventeen  years  old,  for  which 
he  was  operated  on  six  weeks  previous  to  examination ;  appear- 


96  OPTICAL   TRUTHS. 

ance,  anaemic  and  neurasthenic;  habits,  good;  diet,  — ,  with- 
out much  appetite;  dynamic  test,  6.50;  static  test,  T  — ; 
vision,  L.  20/20  R.  20/15;  correction,  L.  +  .75  R.  +  1.00; 
dynamic  test,  with  glasses,  6.50,  static  test,  with  glasses,  o.  k. 
The  fact  that  the  dynamic  test,  when  repeated  shows  no  in- 
crease with  correction  on,  indicates  powerful  control  of  his 
accommodation,  with  a  tendency  to  clonic  spasm,  so  we  regard 
it  as  a  +  symptom.     We  analyze  his  case  as  follows: 

Dynamic  test,  6.50  =  32  years;  as  left  eye  fixes,  add  for 
4-  .75,  8  years,  9  months;  for  mentality,  10  years;  total,  50 
years,  9  months. 

This  gives  a  range  between  the  accommodation  of  an 
emmetrope  at  32  years,  and  that  of  G.  A.  M.  amounting  to  18 
years,  9  months,  the  mid-point  between  the  two  being  41  years, 
41/2  months.  If  he  is  above  it  he  is  in  pretty  good  shape  to 
win  perfect  health.  Speaking  strictly  physically,  if  he  is  above 
40  years,  9  months,  he  is  in  good  shape  and  if  below  40  years, 

9  months,  he  is  in  bad  shape,  but  not  dangerous  unless  he  is 
as  young  as  half  way  down  to  32  years,  which  would  be  36 
years,  41/2  months.  Speaking  strictly  mentally,  he  must  not 
be  less  than  40  years,  9  months,  or  he  would  collapse;  while 
his  maximum  possibility  is  50  years,  9  months;  the  mid-point 
between  these  two  is  45  years,  4  months,  15  days,  which  we  will 
assume  to  be  his  age  on  account  of  +  symptoms  found;  if  he 
is  older  he  is  in  better  shape  than  we  figure  him;  if  he  is 
younger  he  is  in  worse  shape  than  we  figure  him,  and  we  will 
be  governed  in  our  prescription  by  the  result  of  this  calcula- 
tion. A  shorter  way  to  make  the  same  calculation,  so  far  as 
practical  results  are  concerned,  is  to  take  his  6.50  D  accommo- 
dation, which  equals  32  years,  by  table  No.  1  of  the  neurometer, 
add  for  the  error  in  his  fixing  eye  8  years,  9  months,  as  per 
table  No.  2,  less  33  1-3  per  cent  for  his  history,  leaving  5  years, 

10  months,  then  split  the  difference  between  the  minimum 
(5  yrs.)  and  maximum  (10  yrs.),  adding  7  years,  6  months  for 
his  mentality,  making  a  total  of  45  years,  4  months.  He  was 
on  the  date  of  examination  45  years,  4  months,  11  days  old; 


THE  NEUROMETER.  97 

showing  by  the  first  calculation,  four  days  to  the  bad,  and  by 
the  second  calculation  eleven  days  to  the  good.  All  of  which 
proves  the  greatest  drain  on  the  nerve  supply  has  been  in  his 
mental  department.  Part  of  it  U  accounted  for  by  his  abilities 
as  a  mechanical  inventor  and  part  by  the  trouble  from  which 
he  suffered  so  long. 

Case  II.  Dr.  Walter,  an  oculist,  practiced  for  twenty 
years;  history,  indigestion,  headaches  and  "catarrh"  of  gall 
bladder;  difficult  to  get  story  as  he  insisted  on  ridiculing  the 
neurometer,  and  afterwards  beat  the  college  out  of  a  son's 
tuition  fee;  arteries,  o.  k. ;  veins  a  trifle  dark;  dynamic  test, 
4.25;  static  test,  4°  —  impulse;  vision,  L.  20/30,  R.  20/20; 
never  wore  glasses  and  declared  he  had  no  defects  in  his  eyes ; 
correction,  L.  -j-  .50  +  .50  ax.  90;  R.  -f  .50  -f  .50  ax.  90; 
dynamic  test,  5.25;  static  test,  1"  — .  The  neurometer  indi- 
cates 37  years  for  5.25  D.  accommodation  and  his  meridian 
of  greatest  hyperopia  was  1.00  D.,  for  which  we  add  10  years, 
because  his  —  symptoms  were  offset  by  the  -(-  symptoms, 
making  him  47  years  old.  The  examination  was  made  on  the 
18th  of  December,  and  one  of  my  pupils  who  did  it,  threw  off 
one  month  for  the  1°  —  symptom  by  the  static  test,  after 
correction,  so  that  it  figured  46  years,  11  months,  and  as  the 
patient  admitted  he  would  be  47  January  24th,  the  calculation 
showed  him  to  be  six  days  to  the  bad.  Note :  We  add  nothing 
for  his  mentality.    He  had  none  worth  mentioning. 

Case  III.  M.  C,  teacher;  temperament  -j-;  appearance, 
healthy;  complained  only  of  tired  feeling  and  sleepiness  when 
trying  to  do  close  work;  formerly  had  dyspepsia,  headache, 
catarrh ;  had  worn  glasses  many  years,  which  proved  the  proper 
correction;  djmamic  test,  1.75;  static  test,  7°  —  impulse; 
correction,  +  2.50  -\-  .50  ax.  90,  each  eye ;  dynamic,  5.25 ;  static 
test,  4°  —  impulse.  In  this  case,  glasses  having  been  worn 
constantly,  and  the  dynamic  test  showing  less  than  7.00  D.,  we 
suspected  presbyopia,  which  was  corroborated  by  the  fact 
that  the  increase  in  the  showing,  by  the  dynamic  test, 
after  correction  was  only  slightly  greater  than  the  amount 


98  OPTICAL  TRUTHS. 

of  the  error  in  the  worst  meridian;  that  he  was  short 
on  nerve  supply  is  shown  by  the  static  —  impulse  after 
correction  and  by  the  fact  that  he  accepted  readily  -|- 
1.50  addition  for  close  work.  The  fact  that  he  had  been 
wearing  his  correction  several  years,  thus  being  practically 
an  emmetrope,  made  it  necessary  to  make  calculation  as 
follows:  He  worked  at  a  near  point  about  nine  hours 
daily,  six  of  which  are  extra,  for  which  the  neurometer 
says  add  10  years  to  his  showing,  because,  under  such  condi- 
tions the  nerve  demands  about  equal  those  of  1.00  D.  hyper- 
opia, but  we  deduct  25  per  cent  for  —  impulse  by  the  static 
test  and  25  per  cent  for  partial  presbyopia,  leaving  only  5 
years  to  be  added  for  his  close  work.  His  5.25  D.  accommo- 
dation showed  37  years,  to  which  was  added  3  years,  4  monthf 
for  his  error,  and  5  years  for  extra  work,  making  him  45 
years,  4  months  on  the  date  of  the  test,  and  he  was  45  years, 
4  months,  28  days,  or  28  days  to  the  good.  His  mentality  was 
figured  in  his  extra  hours'  work. 

Case  IV.  Miss  B.,  clerk;  appearance,  fairly  good;  com- 
plaints, dysmenorrhoea,  headaches,  difficult  urination,  up  a 
dozen  times  nightly,  and  more  often  during  the  day ;  hyperopia, 
3.25;  dynamic  test,  4.00  D.  before  correction  and  7.00  D.  after; 
static  test,  4°  —  before  and  4°  —  after;  her  accommodation 
after  correction  indicated  30  years,  her  error  called  for  3  years, 
1  month,  15  days  to  be  added,  and,  on  account  of  the  -f-  symp- 
toms shown  in  the  general  examination  no  allowance  was  made 
for  the  —  ones  except  to  add  the  minimum  for  her  work,  which 
is  5  years,  aggregating  38  years,  1  month  and  15  days.  She 
was  38  years,  3  months,  thus  showing  45  days  to  the  good. 

Case  V.  Father  B.,  priest;  appearance,  fair;  complaints, 
catarrh,  indigestion,  headaches;  dynamic  test,  8.00  and  9.00; 
static  test  o.  k. ;  error,  hyperopia,  1.25.  The  neurometer  shows 
23  years,  4  months  for  his  accommodation;  8  years,  9  months 
for  his  error,  and  the  minimum  of  5  years  was  added  for  pro- 
fession to  allow  for  his  —  symptoms,  which  were  not  serious, 
inasmuch  as  he  did  little  close  work ;  total,  37  years,  1  month ; 
he  was  37  years,  2  months,  17  days. 


THE  NEUROMETER.  99 

Case  VI.  Mrs.  T. ;  wife;  tired  from  doing  nothing  but 
the  society  drag;  prolapsus  and  "adhesions";  in  general,  the 
-f-  symptoms  almost  equalled  the  —  ones ;  accommodation,  5.50, 
indicating  36  years,  to  which  was  added  6  years,  3  months,  less 
10  per  cent  for  her  mental  disturbances  over  old  school  doc- 
tors' stories,  or  5  years,  7  months,  15  days;  making  a  total  of 
41  years,  7  months,  15  days.  She  was  41  years,  8  months,  or 
15  days  to  the  good. 

Case  VII.  Mrs.  P.;  trained  nurse;  anaemic  and  neuras- 
thenic; history  of  endometritis  for  nineteen  years;  came  from 
hospital  where  she  had  four  weeks'  rest  after  a  curettement; 
had  been  operated  on  for  "floating  kidney"  two  years  before; 
rheumatism  in  arms  and  feet;  cold  feet  and  hands;  weighed 
1191/2  lbs.;  had  worn  +  1.50  for  several  years;  error  +  3.00 
accommodation  8.00  D.,  equals  26  years,  8  months;  adding  3 
years,  4  months  for  the  entire  errors,  and  7  years,  6  months 
more  for  mentality  made  a  total  of  37  years,  6  months.  She 
was  38  years,  3  months,  or  nine  months  to  the  good,  on  account 
of  her  rest  at  the  hospital,  which  was  the  reason  no  allowance 
was  made  for  her  symptoms,  except  in  adding  for  the  men- 
tality. After  twenty  days  further  rest,  on  strict  diet,  she 
went  to  work,  stronger  than  she  had  ever  been,  and  weighing 
1371/2  pounds. 

Case  VIII.  Miss  C,  teacher;  divergent  squint;  anaemic, 
neurasthenic,  sore  spot  in  back,  couldn't  wear  corset,  head- 
aches, constipation,  indigestion;  measured  8.00  D.,  or  26 
years,  8  months,  and  1.50  hyperopia,  for  which  was  added  7 
years,  6  months,  making  34  years,  2  months.  Deducting  for 
her  —  symptoms,  25  per  cent  for  the  squint,  50  per  cent  for 
the  anaemia  and  neurasthenia,  25  per  cent  for  the  sore  back, 
and  50  per  cent  for  the  headache,  indigestion,  etc.,  aggregating 
one  and  one-half  times  the  amount  added  for  the  error,  or  11 
years,  3  months,  from  34  years,  2  months,  left  22  years,  11 
months,  and  when  she  said  she  was  only  22  years  even,  I  in- 
formed her  if  she  recovered  it  would  be  a  triumph  for  neu- 
rology, as  she  was  below  the  dead-line.    I  fixed  her  back  in 


JOp  OPTICAL   TRUTHS. 

half  a  minute,  straightened  her  eyes  in  two  days,  and  when  she 
showed  amazing  improvement  in  four  days  I  let  her  go  home 
where  she  would  have  absolute  quiet.  In  three  months  she 
reported  well,  gained  21  pounds  and  was  wearing  a  corset 
with  comfort. 

Measurement  of  nerve  strain  caused  by  the  eyes  is  one 
thing,  and  proving  of  our  work  and  casting  up  a  final  account 
for  the  data  is  another. 

Taking  one  at  a  time,  we  first  take  the  prescription  as  it 
comes  from  the  trial  frame,  and  if  there  is  any  plus  in  it,  it 
will  be  in  the  sphere  of  at  least  one  eye,  and  we  base  our  calcu- 
lation thereon.  We  know  that  in  hyperopia  there  is  accom- 
modation and  convergence  and  that  the  convergence  must  be 
neutralized  by  negative  pull,  thus  if  the  eyes  are  equally  de- 
fective, the  amount  of  convergence  and  negative  pull  will  ag- 
gregate an  amount  equal  to  the  accommodation,  therefore  we 
know  that  adding  the  accommodation  of  the  two  eyes  together 
and  multiplying  by  two  gives  the  strain  per  second.  We  know 
that  if  the  two  eyes  are  different,  that  one  will  be  the  fixing 
eye,  and  we  proceed  as  if  the  error  in  the  other  was  the  same — 
this  where  there  is  a  wide  difference  between  the  eyes;  where 
the  difference  is  only  .50  or  less,  we  add  the  spheres  and  multi- 
ply by  two.  If  one  eye  was  hyperopic  1.00  and  the  other  eye 
myopic,  we  would  proceed  as  if  each  were  hyperopic  1.00.  If 
one  eye  was  myopic  and  the  other  simple  hyperopic  astig- 
matism of  1.00,  we  would  figure  as  if  it  was  hyperopia  1.00  in 
each  eye.    In  all  these  cases  we  figure  sixteen  hours  per  day. 

In  figuring  on  a  myope,  we  find  his  far  point  with  naked 
eyes,  make  the  calculation  for  three  hours,  for  accommodation 
and  convergence,  then  proceed  to  measure  his  error  and  deduct 
the  amount  of  his  myopia.  Example :  With  the  dynamic  test 
we  find  the  farthest  point  he  can  read  instead  of  the  nearest. 
Suppose  it  to  be  five  inches,  this  would  mean  for  an  emmetrope : 
8.00  D.  accommodation  in  each  eye,  and  4.00  D.  convergence  in 
each,  or  24.00  D.  in  all.  Then  we  measure  him,  and  find  there 
is  3.00   D.   Myopia  in   each   eye.    Taking   6  from  24  leaves 


THE  NEUROMETER.  JOJ 

18x60x60x3=194,400  D.,  deducting  normal  100,000,  leaves 
94,400  strain. 

In  figuring  the  strain  of  extra  hours'  work,  we  find  the 
distance  same  as  above,  except,  instead  of  the  farthest  point, 
we  find  the  customary  point,  usually  about  13  inches,  which 
would  be  9.00  D.  per  second  for  emmetropia  or  corrected 
h3rperopia.  If  he  is  an  emmetrope,  the  extra  hours'  work  is 
all  the  strain  he  has,  but  if  he  is  an  uncorrected  hjrperope,  we 
add  the  two  amounts  of  strain  together. 

Remember  that  in  putting  glasses  on  hyperopes,  we  save 
the  necessity  for  4.00  D.  per  second  with  a  pair  of  plus  1.00  D. ; 
8.00  D.  with  plus  2.00;  12.00  with  plus  3.00;  16.00  with  plus 
4.00;  but  beyond  that  there  is  not  so  much,  as  patients  rarely 
try  to  overcome  5.00  D.  constantly.  But  the  mere  fact  of  put- 
ting on  these  lenses  does  not  save  all  the  strain  until  the  pa- 
tient relaxes  accommodation  enough  to  see  normally  with 
them.  Next  we  take  up  the  matter  of  the  final  calculation  and 
proof  of  the  work. 

We  first  take  the  dynamic  showing  with  correction  on 
and  refer  to  the  large  table  in  the  neurometer,  which  tells  us 
the  age  of  an  emmetrope  with  that  much  power  shown  in  his 
gauge ;  second,  we  note  the  amount  of  hjrperopia  in  the  greatest 
meridian  (or  strength  of  sphere)  and  turn  to  the  other  table, 
which  tells  us  how  much  the  gauge  is  deceiving  us  by  the  first 
test;  we  add  this  to  the  first  showing,  and  that  tells  us  what 
that  individual  should  show  were  he  an  average  hyperope  of 
the  age  specified.  Next  we  add  from  five  to  ten  years  for 
mentality,  if  the  person  is  doing  work  that  requires  thinking 
and  reading,  and  he  has  an  education,  either  erudite  or  actual ; 
these  additions  are  either  5,  6^4,  7V2»  8%,  or  10  years,  any  one 
who  does  not  merit  the  addition  of  five  years  needs  nothing. 
Low,  5;  low  medium,  6^4;  medium,  71/2;  high  medium,  8%; 
high,  10. 

Whenever  we  can  find  extra  hours'  work  we  figure  on 
them  instead  of  using  the  above,  because  it  is  more  accurate. 
After  having  footed  all  these  figures,  we  show  patient  how  old 


J02  OPTICAL  TRUTHS. 

he  ought  to  be,  then  we  undertake  to  tell  him  how  old  he  is; 
not  that  we  care  to  mystify  anyone,  but  in  order  to  see  if  we 
can  establish  the  value  of  symptoms ;  so  we  make  a  new  table  be- 
ginning with  the  same  figures  as  before,  but,  instead  of  adding 
the  full  amount  of  his  error,  we  deduct,  as  specified  elsewhere, 
and  the  deductions  may  be  as  little  as  5  per  cent,  and  as  much 
as  50  per  cent,  for  any  one  symptom,  the  former  would  be  for 
minor  symptoms,  and  the  latter  for  major  ones,  such  as  a 
combination  of  dysmenorrhea  with  menstruation  every  two 
weeks  and  flooding.  Then  we  would  take  into  consideration 
that  we  should  reduce  our  estimate  for  mentality  almost  in  the 
same  proportion  on  account  of  the  conditions  found.  This  will 
be  found  to  run  a  little  low,  as  a  general  thing,  but  it  gives  a 
better  chance  to  say  encouraging  words  to  your  patient  if  the 
age  is  a  little  more  than  your  figure.  Or  as  the  patient's 
mentality  is  liable  to  be  influenced  by  his  condition,  it  is  a 
little  easier  to  take  the  amount  to  be  added  from  one  of  the 
five  figures  compared  with  an  ideal  standard,  and  make  no 
deductions  at  all. 

Of  course  some  complications  arise  when  one  has  been 
wearing  a  correction  or  part  of  it,  but  when  the  total  strain 
is  figured  first,  we  can  then  judge,  in  making  the  second  calcu- 
lation, by  what  we  have  allowed  for  the  symptoms  present  in 
other  cases  with  that  amount  of  strain,  whether  under  the 
same  circumstances  or  not.  This  proves  the  value  of  having  a 
system.  We  have  an  ideal  eye,  stomach,  liver,  etc.,  and  even 
the  ideal  person ;  more  than  that,  we  have  the  actual  defective 
person  and  organs,  so  that  we  may  master  the  principles  of  our 
own  system  by  practicing  according  to  natural  laws. 


A  MUCH  MOOTED  QUESTION. 

How  to  Treat  Cross-Eyes  and  Alleged  Muscular  Insufficiencies. 

It  is  more  than  passing  strange  how  the  medical  profes- 
sion accepts  assertions  from  self-constituted  authorities  with- 
out putting  them  to  tests.  Long  ago  some  writer  declared 
that  cross-eyes  are  caused  by  paralysis  of  one  of  the  sixth  cra- 
nial nerves  which  operate  the  external  recti,  and  it  has  been 
taken  as  indisputable,  when  if  the  author  of  the  assertion,  or 
those  who  read  after  him  had  possessed  a  modicum  of  knowl- 
edge of  the  mechanics  of  anatomy  and  of  the  possible  causes 
of  derangements  they  could  have  proved  in  one  minute,  or 
less,  that  the  assertion  had  no  foundation  in  fact.  The  test  is 
a  simple  one :  cover  the  fixing  eye  and  direct  the  patient  to  fix 
with  the  other,  without  turning  his  head.  If  he  does  it,  and 
I  have  never  found  one  who  could  not,  unless  the  eye  was 
blind,  it  is  positive  proof  that  the  nerve  is  not  paralyzed. 
Then  it  ought  to  occur  to  a  thinking  doctor  that  it  would  be 
a  queer  state  of  aff'airs  if  one  of  a  pair  of  nerves  should  be 
paralyzed  and  no  others  suffer  the  slightest.  It  is  not  impos- 
sible, but  is  highly  improbable. 

Again,  it  is  a  common  fault  among  doctors  to  be  satisfied 
with  one  theory  of  cause  and  not  look  for  others.  They  wait 
for  the  leaders  to  make  discoveries  while  they  maintain  the 
code  of  ethics '  "air  of  peculiar  reserve ' '  toward  the  laity  and 
talk  about  the  progress  "we"  are  making.  I  have  never  seen 
a  case  of  convergent  cross-eyes  that  was  not  produced  by  one 
of  two  causes,  ametropia  or  operation.  It  is  true  many  cases 
appear  after  the  spasms  of  whooping  cough  or  irritation  or  ex- 
haustion from  other  disorders,  but  the  primary  cause  was 
defect  in  the  physical  proportions  of  the  eyes.  This  has  been 
proved  hundreds  of  times  by  myself  and  my  pupils  by  cor- 
recting the  defects,  or  overcorrecting  them  for  a  time,  when 
the  eyes  straightened  without  further  assistance.  It  is  very 
rarely  that  operation  is  needed  and  when  we  are  a  little  wiser 
I  am  sure  it  will  never  be  done. 


J04  OPTICAL   TRUTHS. 

In  cases  of  cross-eyes,  from  other  cause  than  operation, 
both  eyes  deviate,  but  the  necessity  for  vision  impels  the  fixing 
of  one  eye  by  the  controlling-  center,  (one  of  the  most  perfect 
illustrations  of  Nature's  power  of  adapting  herself  to  circum- 
stances), while  the  other  is  permitted  to  do  all  the  turning. 
Sometimes  the  eyes  alternate  in  fixing  and  as  such  are  the 
easiest  to  straighten  by  our  method,  we  have  learned  that  it  is 
a  good  idea,  in  other  cases,  to  first  create  this  tendency  by 
covering  the  fixing  eye  and  compelling  the  other  to  fix.  In 
little  children  we  are  often  able  to  straighten  the  eyes  without 
glasses  by  using  such  tactics  and  strengthening  the  general 
nerve  supply  by  a  positive  diet.  Of  course,  if  that  fails  we 
know  it  is  because  we  did  not  remove  the  cause,  and  we  resort 
to  glasses.  The  only  reason  we  do  not  put  glasses  on  in  the 
beginning  is  that  while  we  know  the  error  of  refraction  is 
there,  we  know  that  if  a  system  is  in  perfect  order,  in  every 
other  particular,  the  excess  nerve  demands  of  the  eyes  can  be 
supplied  without  danger  to  health,  at  least  for  several  years, 
and  it  is  to  let  the  little  one  go  without  the  inconvenience  of 
glasses  if  possible.  Of  course,  if  there  are  complications,  such 
as  headache,  constipation,  fits,  etc.,  we  use  every  precaution  to 
insure  winning  from  the  beginning.  Then,  occasionally,  when 
the  child  has  grown  strong,  we  try  laying  aside  the  glasses 
always  remembering  and  informing  the  guardians  that  in  sc 
doing  there  is  some  risk  of  the  eyes  crossing  again;  but  if 
they  do,  we  can  do  the  work  over. 

The  manner  in  which  hyperopia  causes  convergent  stra- 
bismus will  be  understood  best  by  first  comprehending  the 
normal  relation  between  convergence  and  accommodation. 

Fig.  56  shows  the  two  eyes  fixed  on  a  point.  A,  say  13 
inches  distant,  the  axes  of  the  two  eyes  each  turning  in  to  the 
median  line,  and  the  accommodation  working  so  that  A  and 
B  B  are  in  conjugate  focus.  The  latter,  being  two  independent 
duties,  each  requires  3.00  D.  effort  from  the  nervous  system, 
while  the  former,  being  a  joint  duty,  only  requires  a  total  of 
3.00  D.,   or  1.50   each,   delivered  through  the  internal  recti 


A  MUCH-MOOTED  QUESTION. 


105 


muscles  from  branches  of  the  third  nerves  that  operate  the 
accommodation.  All  is  under  direction  of  the  controlling  cen- 
ter, C,  back  in  the  brain;  it,  in  turn,  receiving  its  impulses 
from  the  nerves  of  sensation,  the  second  or  optic  nerves.    As 


Fig.   56 


J06  OPTICAL  TRUTHS. 

this  is  the  natural  situation,  and  as  such  functions  belong  prac- 
tically to  the  sympathetic  or  involuntary  system,  let  us  express 
it  as  follows: 

An  emmetrope  working  at  13  inches  requires  from  the 
nervous  system:  For  accommodation,  L..  3.00  D.,  R.  3.00  D.; 
for  convergence,  L.  1.50  D.,  R.,  1.50.  D. ;  total,  9.00  D. 

In  order  to  put  this  in  still  more  comprehensive  form,  let 
one  second  be  the  unit  of  time  in  our  calculations.  Thus,  if 
it  requires  9  D.  for  one  second  at  the  13  inch  point  it  will 
require  60  times  9  D.  per  minute  or  540  D.,  and  60  times  that 
per  hour,  or  3,240  D. ;  the  average  number  of  minutes  close  work 
daily  is  only  about  three  hours,  so  that  the  total  demands  of 
these  two  functions  is  only  97,200  D.  daily. 

Now  take  a  hyperope  of  a  3  D.,  who  must  use  his  accom- 
modation unnaturally  on  account  of  the  defect  in  the  form  of 
the  eye-balls,  but  who  has  exactly  the  same  anatomical  rela- 
tions between  accommodation  and  convergence.  He  cannot 
accommodate  without  converging  and  while  the  accommoda- 
tion only  brings  his  retina  in  conjugate  focus  with  objects  at 
infinite  distances,  his  convergence  brings  the  axes  to  a  point 
13  inches  away.  The  only  things  left  for  the  controlling  cen- 
ter to  do  are,  either  fix  with  one  eye  and  let  the  other  turn  in 
toward  a  point  6i/o  inches  from  the  face,  or  send  enough 
energy  to  the  external  recti,  over  the  sixth  nerves,  to  hold  the 
axes  parallel  in  spite  of  the  convergent  pull.  Thus,  there  is  a 
twofold  strain  on  the  hyperope:  First,  his  demand  is  all  in 
excess  of  normal;  second,  it  forces  nerves  which,  ordinarily, 
work  alternately,  to  work  at  the  same  time.  It  follows,  natu- 
rally, that  when  the  nerve  supply  under  control  of  C  becomes 
weakened,  the  first  place  the  innervation  is  withdrawn  will  be 
from  the  sixth  nerves,  thus  after  an  attack  of  acute  disturb- 
ance, such  as  typhoid,  scarlet  fever,  diphtheria,  or  weakening 
from  other  cause,  the  eyes  are  liable  to  cross.  Or,  if  there  be 
spasms,  such  as  from  whooping  cough,  the  irritation  would 
give  the  third  nerves  an  advantage  over  the  sixth  and  the  eyes 
may  turn. 


A  MUCH-MOOTED  QUESTION.  J07 

The  nerve  demand  in  a  hjrperopia  of  a  3.00  D.  would  be 
as  follows :  For  accommodation,  L.  3.00,  R.  3.00 ;  for  automatic 
convergence,  L.  1.50,  R.  1.50 ;  for  negative  pull,  via  6th  nerves, 
to  prevent  convergence,  R.  1.50,  L.  1.50;  total,  12.00  D. 

Therefore,  12  D.  for  one  second  means  720  D,  for  one  min- 
ute, 43,200  D.  per  hour,  and  691,200  D.  per  day  of  16  hours, 
which  is  the  average  time  people  are  awake  daily.  Then  if 
this  person  is  required  to  do  the  average  number  of  hours  close 
work  daily  his  total  demand  is  788,400  D.  daily  against  the 
normal  demand  of  only  97,200  D.  Is  it  any  wonder  he  be- 
comes cross-eyed?  Is  it  not  remarkable  that  there  are  not 
more  cross-eyed  ones?  Is  the  assertion  that  eye  strain  is  one 
of  the  chief  causes  of  human  ills  a  claim  to  be  ridiculed  or 
disputed?    It  is  only  done  nowadays  by  utter  ignoramuses. 

The  philosophy  of  my  treatment  of  convergent  squint 
should  be  clear  now:  Simply  correct  the  error  that  requires 
the  accommodation,  thus  doing  away  with  the  convergence, 
which  in  turn  makes  the  divergent  pull  unnecessary.  This  is 
the  proof  that  every  -f  sphere,  worn  constantly  for  the  correc- 
tion of  hyperopia,  saves  twice  as  many  nerve  units  per  second 
as  the  lens  has  units  of  power.  But  it  is  not  so  simple  a  propo- 
sition when  it  comes  to  the  solving  practically.  The  operator 
must  not  only  know  the  anatomy  and  physiology  of  the  eyes 
particularly  and  of  the  system  generally,  the  sympathetic  re- 
lationship between  organic  functions,  etc.,  but  he  must  know 
physics  and  mechanics  and  have  a  natural  tact  and  adeptness, 
not  possessed  by  everyone,  to  measure  the  errors  correctly. 
The  assertion  by  some  would-be  oracles  that  none  but  physi- 
cians are  competent  to  fit  glasses  to  the  eyes  is  foolish  in  view 
of  the  fact  that  very  few  physicians  ever  used  a  set  of  trial 
lenses  or  received  any  instruction  whatever  about  eyes,  except 
possibly  something  about  pathology  of  the  eyes,  and  that  was 
false.  Ask  the  first  ten  physicians  you  meet;  be  practical. 
The  assertion  is  on  a  par  with  another,  by  the  same  wiseacres, 
that  no  one  can  get  an  eye  correction  without  first  using  a 
cyclopegic.    They  are  the  same  individuals  who  declare  that 


108  OPTICAL  TRUTHS. 

the  old  schools  of  medicine  have  patent  rights  on  all  discovered 
or  undiscovered  methods  of  relieving  human  ills,  and  expose 
themselves  to  ridicule  and  fear  for  their  sanity  by  saying: 
"It  is  better  that  a  patient  die  in  the  hands  of  a  regular  phy- 
sician than  recover  under  the  ministrations  of  an  empiric. ' '  It 
is  the  favor  new  schools  are  meeting  in  the  estimation  of  an 
intelligent  public  that  drives  them  frantic. 

An  ophthalmologist,  treating  convergent  squint,  begins  by 
disregarding  vision  to  the  extent  of  prescribing,  for  temporary 
wear,  such  +  glasses  as  will  blur  the  vision  of  the  fixing  eye 
for  distant  objects  until  it  is  worse  than  the  other,  provided, 
always  that  the  other  has  enough  to  enable  the  patient  to  see 
sufficiently  to  take  care  of  himself.  Often,  on  returning  in  a 
few  days,  vision  will  have  improved  very  much;  then  we  blur 
some  more,  until  the  spasms  in  the  ciliary  nerves  and  those  of 
the  intemi  have  relaxed  and  the  eyes  are  straight,  when,  if 
vision  is  not  perfect,  we  give  the  correction  that  will  make  it 
as  nearly  so  as  is  possible.  Sometimes  the  blurring  process  is 
not  successful  because  the  temperament  of  the  patient  is  such 
that  he  adapts  himself  too  readily  to  any  situation.  In  such 
instances  we  reduce  the  blur  for  a  few  days  to  excite  the  desire 
to  see,  and  thus  set  up  influences  for  reaction.  If  one  eye  is 
totally  blind  it  makes  little  diff'erence  in  the  proceeding;  we 
blur  the  good  eye  to  about  20/50  or  20/60,  stop  all  close  work 
and  get  the  system  in  good  condition  by  diet,  rest,  etc.,  as  we 
should  do  in  all  cases,  when  the  blind  eye  will  straighten, 
affording  the  best  possible  proof  our  philosophy  is  correct.  If 
one  eye  turns  up  or  down,  treat  in  the  same  manner. 

If  the  deviation  is  outward  it  is  from  deficiency  to  the 
point  of  exhaustion  at  the  time  it  occurred,  or  from  blindness 
in  one  eye  which  disconnected  it  from  the  controlling  center. 
Theoretically  the  practice  suggested  for  convergence  should 
not  work,  but  by  modifying  it  a  little  we  are  often  able  to 
get  fine  results,  provided  the  deviating  eye  can  see.  If  the 
patient's  nerve  supply  measures  below  normal  we  blur  the 
good  eye  and  barely  correct  the  other,  to  force  it  into  action, 


A  MUCH-MOOTED  QUESTION.  J09 

then  tone  up  the  system  with  dietary,  rest,  etc.  In  all  cases 
no  harm  is  done  by  having  the  patient  turn  the  deviating  eye 
to  the  opposite  side  as  far  as  possible,  the  lids  being  closed, 
then  the  operator  holds  it  by  gentle,  firm  pressure,  while  pa- 
tient tries  to  turn  it  back ;  teach  the  patient  to  do  it  himself  at 
frequent  intervals. 

The  length  of  time  required  to  complete  the  work  of  get- 
ting cross-eyes  to  work  together,  straight,  varies,  from  a  few 
seconds  to  several  months.  Something  depends  on  the  men- 
tality of  the  patient  and  something  on  the  physical  tempera- 
ment, just  as  in  all  other  things.  The  operating  fiend  objects 
that  it  takes  too  long.  We  reply  that  operations  made  unnec- 
essarily are  a  crime,  hence  nearly  if  not  quite  all  cross-eye 
operations  are  crimes.  He  says,  "But  your  patients  have  to 
wear  glasses."  We  reply,  "So  do  yours;  if  they  do  not  they 
soon  require  another  operation,  and  another  until  the  eyes  are 
finally  worthless. ' '  Almost  half  of  the  total  number  of  diver- 
gent squint  cases  I  have  met  testified  their  eyes  formerly  turned 
in  but  were  operated,  then  turned  out,  aiid  they  were  afraid 
to  let  the  alleged  surgeon  do  any  more  cutting.  There  is  also 
more  or  less  danger  of  blood-poisoning  after  operations. 

But  cutting  muscles  for  cross-eyes  is  a  mild  crime  com- 
pared with  the  slashing  oculists  do  for  that  mjrth  "muscular 
imbalance."  I  have  made  an  assertion  and  the  proof  is  due. 
First,  let  me  make  others  and  I  will  then  proceed  to  prove  all 
at  once:  They  all  apply  what  they  call  muscle  tests.  The 
first  one  comprises  the  Maddox  rod,  or  double  prism  on  one 
eye  and  a  colored  glass  on  the  other.  We  prefer  to  use  the 
double  prism  because  it  is  simpler  than  the  Maddox  rod. 
Let  the  colored  glass  be  on  the  right  eye  for  this  illus- 
tration. When  adjusted  properly  and  looking  with  both 
eyes  the  patient  should  see  the  colored  light  in  line  with 
and  midway  between  the  other  two,  all  in  a  vertical  posi- 
tion, and  when  he  does  it  is  called  orthophoria  or  a 
normal  state;  but  if  the  red  light  is  seen  to  the  right 
they  say  the  right  eye  is  turning  in  from  a  weakness  of  the 


no  OPTICAL   TRUTHS. 

external  rectus  muscle,  and  as  esophoria  means  a  tendency 
inward  they  apply  that  word  to  the  condition  and  declare  they 
must  cut  the  internal — because  the  external  is  weak!  If  the 
red  light  appears  to  the  left  it  means  to  them  that  the  internal 
rectus  of  that  eye  is  weak — and  they  cut  the  external!  They 
call  this  exophoria,  because  they  think  the  right  eye  turns  out. 
If  the  red  light  appears  above  the  mid-point  they  call  it  left 
hyperphoria,  if  below  that  point,  right  hyperphoria — one  of 
them  calls  it  left  ' '  cataphoria, ' '  but  as  catoptrics  is  the  science 
of  reflections  we  pass  liim.  They  apply  the  term  heterophoria 
to  all  deviations.  To  recapitulate  briefly,  they  say  that  in  all 
imbalances  the  fault  is  in  the  muscles,  that  it  is  always  weak- 
ness of  the  muscle  on  the  opposite  side  of  the  eye  from  the 
way  it  turns  and  that  the  eye  turns  opposite  to  the  way  the 
light  deviates.  I  say,  both  eyes  turn,  which  is  easily  proved, 
theoretically,  by  the  anatomical  and  physiological  relationship 
existing  between  them,  and  practically  by  reversing  the  prisms 
and  colored  glass,  the  latter  being  on  the  left  eye  will  show 
as  much  deviation  as  was  shown  by  the  first.  I  am  almost 
afraid  to  tell  them  this  lest  they  cut  the  muscles  of  that  eye 
too.  And,  lest  someone  be  misled  by  a  difference  in  the  amount 
of  deviation  when  the  test  is  made,  let  it  be  remembered  that 
repeated  tests  with  the  first  arrangement  will  often  show  dif- 
ferent amounts  of  prism  required  to  get  the  lights  in  line,  just 
as  the  patient  grows  more  passive  or  more  irritated  by  the 
test.  I  say,  further,  that  in  the  so-called  heterophoria  the 
eyes  deviate  the  same  way  the  lights  appear  to,  hence  what 
they  call  esophoria  is  really  exophoria  and  what  they  call 
exophoria  is  really  esophoria,  while  what  they  call  right  hyper- 
phoria, that  is,  right  tending  upward,  is  really  a  downward 
tending,  and  when  they  say  it  turns  downward  it  is  really 
tending  upward.  Also  what  they  call  hyperphoria  is  often  a 
vertical  squint  or  hypertropia,  as  they  would  call  it,  to  class  it 
with  cross-eyes.  Finally,  I  say  what  they  call  muscular  im- 
balance is  not  muscle  trouble  at  all,  but  is  due  solely  to  irri- 
tation or  weakness  of  the  nerve  supply  in  the  cerebellum.    All 


A  MUCH-MOOTED  QUESTION.  Ui 

of  which,  if  true,  proves  their  operations  to  be  crimes,  com- 
mitted through  ignorance  or  willfully.  The  reason  I  added 
the  word  "willfully"  is  because,  if  they  find  the  eyes  in  per- 
fect balance  by  the  test  described  they  have  another  called 
the  duction  test,  which  they  apply,  after  having  fixed  an  ar- 
bitrary standard  of  power  each  set  of  coordinate  muscles 
should  exhibit  and  if  one  set  shows  more  power  than  the 
standard  they  cut  it;  if  it  shows  less,  they  cut  its  antagonist. 
They  put  on  strong  prisms,  apices  over  the  muscles  to  be 
tested  and 

The  interni  must  overcome  not  more  than  24"^  or  less 
than  20". 

The  extemi  must  overcome  not  more  than  8^  or  less 
than  6\ 

The  superior  must  overcome  not  more  than  4°  or  less 
than  3\ 

The  inferior  must  overcome  not  more  than  4°  or  less 
than  3". 

Thus  they  discover  what  they  call  "latent"  muscle 
troubles.  One  of  my  students,  aged  60,  exhibited  by  this  test, 
8^  with  the  interni,  3°  with  the  extemi,  and  1°  with  the  supe- 
rior and  inferior,  so  I  wrote  one  of  the  partisans  of  the  test  to 
find  which  muscles  to  cut,  inasmuch  as  by  his  theory  they  all 
should  catch  it,  but  I  never  received  a  reply.  I  did  not  expect 
one. 

Now  for  the  proofs:  None  will  deny  that  motor  nerves 
are  the  sole  source  of  power  to  move  muscles  voluntarily.  All 
will  admit  a  certain  elasticity  of  the  fibrous  structure,  but  it 
is  always  negative  in  straight  muscles.  Hence  muscles  are 
only  the  mediums  through  which  nerve  force  is  applied,  just  as 
engines  are  only  the  mediums  through  which  steam  and  elec- 
tricity are  applied.  Then,  if  we  have  a  case  of  spasm  of  ac- 
commodation it  is  irritation  of  the  nervous  system  at  being 
called  on  to  work  overtime,  and  it  is  but  natural  that  other 
Tjranches  of  the  same  nerves  would  feel  the  extra  current,  par- 
ticularly those  operating  the  coordinate  function  with  accom- 


n2  OPTICAL   TRUTHS. 

modation,  namely,  the  convergence,  and,  when  the  double  prism 
and  colored  glass  test  is  applied  we  would  expect  the  eyes  to 
deviate  inward  as  soon  as  control  was  taken  from  C,  (Fig.  56), 
and  if  the  eyes  carry  the  lights  in  the  same  direction  they 
turn,  the  red  light,  on  the  right  eye,  should  appear  to  the  left 
of  the  others,  while  the  others  should  appear  to  the  right  of 
the  red;  in  other  words  the  lights  should  cross  over  because 
the  axes  do.     Now  let  us  see  if  they  do. 

First  take  a  vigorous  person  with  no  presbyopic  tendency 
and  put  the  double  prism  on  the  left  eye,  the  other  being  cov- 
ered, and  have  him  look  at  a  small  spot,  say  as  large  as  a  pin 
head,  on  a  piece  of  white  paper  at  about  six  inches  from  his  face, 
and  adjust  the  prism  so  he  sees  two  spots  in  a  vertical  position. 
Note  how  the  eyes  are  converging,  then  uncover  the  right  eye, 
when  he  will  tell  you  the  middle  spot  is  decidedly  to  the  left. 
Then  take  a  person  with  a  presbyopic  tendency,  but  who  can 
still  accommodate  some,  and  try  the  same  test,  when  his  right 
eye  will  fail  to  bring  the  middle  spot  even  with  the  others. 
Then  draw  a  line  through  the  spot  and  repeat  the  test  on  both, 
when,  unless  the  first  one  has  a  tonic  spasm,  or  cramp,  he  will 
see  all  the  spots  on  the  line,  and,  the  second  will  do  the  same, 
unless  his  presbyopic  tendency  is  very  strong.  This  experi- 
ment proves  two  things:  First,  that  the  object  deviates  the 
same  way  the  eyes  turn;  second,  that  the  dot-and-line  test  as 
they  use  it,  to  find  " heterophoria  at  the  near  point,"  is  worse 
than  worthless. 

Fig.  57  shows  an  esophoria,  or  inward  tending  of  the  eyes, 
under  the  test.  I  have  drawn  the  deviation  all  in  one  eye  in 
order  to  make  the  illustration  simpler.  The  left  eye,  with  the 
double  prism,  sees  two  lights  at  twenty  feet,  one  above  and 
the  other  below  the  axis  at  the  macula  because  the  prisms  are 
of  equal  strength;  and  its  axis  is  in  direct  line  with  the  real 
light,  because  we  permit  the  patient  to  fix  before  uncovering 
the  other  eye.  The  other,  when  uncovered,  gives  way  to  the 
positive  or  negative  impulse  present  because  the  two  eyes  are 
thrown  out  of  gear  and  the  controlling  center,  not  being  able 


A  MUCH-MOOTED  QUESTION. 


n3 


to  focus  its  image  with  the  other  two,  simply  lets  it  drift  with 
general  conditions.    In  this  case  it  is  a  positive  impulse,  also 


t 


Fig.   57 


JH  OPTICAL  TRUTHS. 

exhibited  by  spasm  of  accommodation  and  of  sphincter  nerves 
throughout  the  body,  so  the  axis  A  turns  in  from  the  normal 
line  X  which  is  the  exact  direction  of  the  object.  The  turn  is 
so  slight,  however,  that  the  ray,  X,  crosses  the  axis.  A,  before 
reaching  the  lens,  and  is  broken  back  toward  the  axis  so  that 
it  strikes  the  macula  as  nearly  the  center  as  either  of  the 
images  in  the  other  eye  can  be,  and,  as  the  direction  from  the 
lens  to  M  is  as  if  the  ray  came  from  0,  the  light  appears  to  be 
at  0.  If  from  weakness  of  the  supply  to  the  third  nerve 
branches  the  eyes  deviate  apart  when  thrown  out  of  gear,  the 
lines  0  and  A  would  be  on  the  other  side  of  the  line  X.  The 
prism,  apex  toward  the  position  where  the  center  light  should 
be,  which  puts  the  deviating  lights  in  line,  does  not,  as  they 
think,  measure  the  amount  of  the  deviation  in  degrees.  It 
merely  indicates  the  relative  intensity  of  the  spasm  or  the 
extent  of  the  weakness  in  the  nervous  system,  as  is  proved 
readily  by  measuring  the  distance  of  the  deviation  in  inches 
and  observing  that  while  it  may  remain  the  same  at  different 
tests  the  amount  of  prism  required  to  supply  the  impulse  to 
put  the  lights  in  line  is  variable.  Also,  one  person,  with  a 
deviation  of  twelve  inches,  may  require  a  12°  prism  while 
another  with  greater  deviation  may  need  less.  The  best  way 
to  take  these  measures  is  to  have  a  strip  of  white  paper  several 
feet  long  on  the  wall,  with  the  light  hanging  exactly  in  the 
middle,  and  through  the  middle  of  the  paper  have  a  plain, 
black  line,  half  an  inch  wide,  with  vertical  lines  drawn  through 
it  every  few  inches.  This  will  appear  in  duplicate  through 
the  double  prism;  then  have  the  patient  tell  where  the  red 
light  is  with  reference  to  these  lines. 

The  ophthalmologist  uses  this  test,  not  as  a  muscle  or  eye 
test,  but  as  a  static  test  of  the  state  of  the  general  nerve  supply. 
He  would  no  more  think  of  prescribing  prisms  for  such  devia- 
tions than  he  would  think  of  cutting  muscles,  and  he  would  no 
more  cut  muscles  than  he  would  cut  throats.  We  never  sup- 
plant nature,  and  we  never  try  to  assist  her  unless  we  know 
exactly  why  we  do  what  we  do.    When  this  test  is  off,  the  eyes 


A  MUCH-MOOTED  QUESTION.  JJS 

are  in  gear  and  the  controlling  center  supplies  all  the  impulse 
necessary. 

Then  there  is  another  "phoria,"  called  cyclophoria,  in 
which  the  eyes  turn  on  their  optical  axes  and  present  oblique 
astigmatism  when  the  principal  meridians  should  be  vertical 
and  horizontal.  If  there  is  a  spasm  of  the  nervous  system  it 
may  exhibit  in  the  inferior  oblique  muscles  and  pull  the  eyes 
inward  below,  rolling  the  tops  outward,  or,  if  there  is  nerve 
exhaustion,  the  inferior  oblique  will  be  enervated,  letting  the 
superior  oblique  pull  in  at  the  top,  from  its  elasticity,  when 
there  is  less  resistance  than  usual,  rolling  the  lower  parts  out- 
ward. The  reason  in  both  cases  is  that  the  inferior  oblique  is 
operated  by  the  same  nerves  that  supply  the  accommodation 
and  the  internal  recti,  hence  the  tension,  or  lack  of  it,  on  all 
muscles  operated  by  the  same  nerves.  A  test  for  cyclophoria, 
which  is  not  reliable,  however,  is  to  put  the  double-prism  on 
one  eye  and  adjust  it  so  that  a  patient  looking  at  a  horizontal 
line,  about  half  an  inch  wide  and  fifteen  or  twenty  feet  away, 
will  see  two;  then  uncover  the  other  eye  when  he  should  see 
a  third,  midway  between  and  parallel  with  the  two  seen  by  the 
first  eye.  If  the  nasal  ends  tilt  downward,  the  principal  merid- 
ians nearest  horizontal  are  tilting  upward,  indicating  a  spasm 
of  the  nervous  system,  exhibited  through  the  inferior  oblique 
muscles;  if  the  nasal  ends  tilt  upward  it  indicates  the  prin- 
cipal meridians  are  tilting  downward  from  nervous  weakness, 
exhibited  through  the  inferior  oblique  muscles.  This  is  just 
opposite  to  the  indications  by  the  test  with  cylinders,  when 
there  is  astigmatism,  because  then  we  have  the  positions  of  the 
principal  meridians  indicated  by  the  axes  of  the  cylinders. 
The  reason  the  prisms  and  line  test  is  worthless  is  the  same 
that  makes  the  dot-and-line  test  a  nullity,  viz. :  the  lines  offer 
the  controlling  center  a  guide  and  it  often  takes  the  hint  dis- 
closing no  disturbance  because  the  parallelism  of  the  lines  is 
maintained.  In  all  cases  where  there  is  doubt  about  the  loca- 
tion of  the  axes,  prescribe  -(-  spheres.  It  is  proper  to  say  that 
when  astigmatism  is  great  enough  to  impair  vision  seriously  it 
rarely  creates  nervous  effort  enough  to  upset  the  system. 


n6 


OPTICAL   TRUTHS. 


The  treatment  indicated  by  -f-  impulses  is  stop  the  cause 
of  spasm  by  correcting  the  hyperopia  and  the  symptoms  dy- 
namic and  static  will  soon  disappear.  If  there  are  —  impulses 
they  mean  rest  in  addition  to  the  correction.    In  connection 

^- 
/ 


Fig.   58 


A  MUCH-MOOTED  QUESTION.  JJ7 

with  both  we  find,  often,  other  causes  of  disturbance  and  we 
remove  all  of  them  without  operation,  except  a  few  hopeless 
cases  who  must  be  content  to  take  the  chances  of  operation, 
which,  if  successful,  can  only  keep  alive  what  is  left ;  they  are 
never  whole  afterward.  We  send  them  to  those  who  boast 
they  would  rather  operate  than  eat — we  prefer  to  eat  and 
think  we  are  greater  surgeons  when  we  can  save  a  person 
whole  than  those  who  take  chances  wholly  unnecessary  and 
refuse  to  investigate  our  methods,  but,  nevertheless,  condemn 
them  even  to  libeling  us. 

"But,"  you  say,  "how  did  your  opponents  get  the  idea 
that  in  heterophoria  the  eyes  deviate  opposite  to  the  way  the 
lights  do?"     All  right,  I'll  answer  that,  too. 

Fig.  58  shows  two  eyes  fixing  on  a  point  six,  or  eight,  or 
more  inches  away,  and  X  X  represent  rays  coming  from  a  light 
fifteen  or  more  feet  distant.  While  only  one  image  of  0  will 
be  conveyed  to  the  brain,  there  will  be  two  of  the  distant  ob- 
ject; they  will  be  imperfect,  that  is,  not  clear,  because  the  eyes 
are  in  conjugate  focus  with  the  nearer  point  and  because  the 
retinal  impressions  are  not  made  on  a  highly  sensitive  part — 
some  of  the  image  falling  on  the  blind  spot — and  as  refraction 
by  both  cornea  and  lens  is  in  the  outer  hemisphere  the  lights 
appear  in  the  directions  X^  X'  on  the  dash  lines.  This  is  be- 
cause the  convergence  of  the  two  eyes  is  beyond  the  limit 
angle.  The  reader  may  try  this  and  will  find  it  true  that  when 
the  eyes'  axes  turn  so  much  with  reference  to  a  line  toward  a 
distant  object,  the  object  will  exhibit  the  opposite  deviation. 

Fig.  59  shows  a  left  eye  fixing  and  the  right  eye  doing  the 
turning  perceptibly,  so  that  a  ray  from  the  object  0  appears 
as  if  located  at  0%  If  the  eye  turned  out  the  lines  Ax  and  0- 
would  be  reversed.  When  we  are  working  with  cross-eyes  and 
the  patient  complains  of  seeing  double  we  know  we  are  getting 
along  with  the  case  nicely  and  as  soon  as  the  controlling  cen- 
ter gets  a  hold  the  eyes  will  straighten  and  remain  straight. 
Usually  the  deviating  eye  turns  enough  to  let  the  image  fall 
on  its  blind  spot  so  it  does  not  send  any  image  to  the  brain, 
which  relieves  mental  worry. 


ns 


OPTICAL   TRUTHS. 


^::^ 


Figr.   59' 


Fig.  60  shows  another  situation  which  the  reader  may 
try.  Fix  the  eyes  on  the  distant  object  so  that  the  axes  are 
parallel,  as  are  X  X  in  the  cut,  then  hold  a  pencil,  or  the  finger, 


A  MUCH-MOOTED  QUESTION. 


n9 


a  few  inches  away,  when  there  will  appear  to  be  two,  the  right 
eye  seeing  the  one  on  the  left  and  the  left  eye  seeing  the  one 
on  the  right,  as  shown  by  the  dash  lines.  This  is  because  the 
visual  axes  are  beyond  the  limit  angle  for  rays  from  the  near 

\    A  / 


Fig.   60 


J20  OPTICAL   TRUTHS. 

point.  This  shows  how,  if  the  eyes  turn  out,  a  distant  object 
would  be  seen  as  two,  deviating  opposite  to  the  direction  the 
eyes  turn,  except  when  they  turn  so  far  one  does  not  partici- 
pate in  vision  at  all. 

My  answer  then,  is:  My  critics  think  because  the  lights 
deviate  opposite  to  the  turn  of  the  eyes  in  strasbismus  it  must 
be  true  in  all  cases,  whether  the  eye  turns  perceptibly  or  not, 
which  proposition  is  false  as  I  have  proved,  anatomically, 
physiologically,  physically  and  clinically  here,  while  several 
hundreds  pupils  and  myself  have  proved  it  in  practice  so  long 
that  it  seems  almost  absurd  to  give  it  so  much  space  at  this 
time. 

So  long  as  the  deviation  of  the  eyes  does  not  disfigure  the 
appearance  there  is  no  squint  and  when  there  is  squint  there 
is  no  need  for  a  muscle  test  to  tell  which  way  the  deviation  is. 
When  there  is  no  deviation  except  as  exhibited  by  the  test  the 
eyes  always  deviate  in  the  same  direction  the  lights  do.  I 
think  that  is  stated  plainly  enough,  and  proved  by  the  figures. 

Vertical  deviations  show  squint  and  exhibit  diplopia  with 
less  amount  of  turn  than  in  any  other  direction  because  the 
superior  and  inferior  recti  are  operated  by  the  same  nerve 
branches  and  thus  reach  their  limit  angles  quicker  as  is  illus- 
trated by  the  duction  test. 


SOME  PRISM  FIGURES 

Which  Prove  the  Fallacy  of  Claims  for  Them  as  Therapeutic 

Agents. 

As  refracting  mediums  and  therapeutic  agents  prisms 
offer  two  distinct  propositions.  The  first  has  been  treated  in 
the  chapter  on  physics  and  the  other  is  due  to  receive  attention. 

Take  an  emmetrope,  or  an  ametrope,  in  good  condition,  so 
that  the  static  test  shows  the  three  lights  in  line,  and  watch  his 
eyes  as  you  drop  in  front  of  them  a  10-degree  prism,  base  out. 
You  will  see  them  turn  in  perceptibly.  The  one  on  which  the 
prism  is  placed  will  turn  in  at  once  while  the  other  will  turn 
out  first,  then  in,  as  soon  as  it  finds  the  first  stop.  This  is  be- 
cause the  first  impulse  to  the  other  eye  was  transmitted  by  way 
of  the  optic  commissure  and  the  second  by  the  controlling  center 
when  it  discovered  the  situation.  Now  make  a  long  horizontal 
line  on  the  wall,  in  the  middle  of  it  hang  a  light ;  on  either  side 
of  the  light  draw  short  vertical  lines  about  two  inches  apart, 
making  them  plain  enough  to  be  seen  readily;  then,  with  the 
two  lights  seen  through  the  double  prism  and  the  red  one  seen 
by  the  other  eye,  all  in  line,  suddenly  impose  a  4-degree  prism 
base  out  in  front  of  the  red  glass  and  have  the  patient  state 
the  amount  of  the  deviation  caused  by  locating  the  position  of 
the  red  light  with  reference  to  the  short  vertical  lines,  which 
will  of  course  appear  as  two  sets  through  the  double  prism 
(have  patient  ignore  all  seen  with  the  red  eye,  excepting  the 
light).  Remove  the  trial  frame  and  take  two  strings,  each 
long  enough  to  reach  from  the  patient  to  the  wall;  have  him 
hold  two  ends,  one  under  each  pupil,  while  the  operator  takes 
the  other  two  ends  and  holds  them  taut  at  the  points  where 
the  light  is  and  where  the  displacement  located  it,  the  string 
from  what  was  the  red  eye  running  to  the  displaced  position 
and  the  other  to  the  real  position.  These  represent  the  true 
visual  axes  of  the  two  eyes  under  the  test  and  the  distance 
from  the  face  to  the  point  where  they  cross  shows  the,  exact 


J22  OPTICAL   TRUTHS 

angle  of  convergence  caused  by  the  prism.  It  will  be  found 
to  be  approximately  one  meter  in  tests  of  normal  eyes,  hence 
we  know  that  a  4-degree  prism  base  out  causes  practically  one 
meter-angle  of  convergence,  requiring  .50  D.  effort  in  each  eye. 
Inasmuch  as  when  such  effort  is  caused  in  a  natural  way  by  a 
demand  for  accommodation,  and  as  putting  prisms  on  emme- 
tropic eyes  (or  on  fully  corrected  ametropic  eyes),  causes  dim- 
ness of  distant  vision,  we  know  the  impulse  to  converge,  even 
when  caused  artificially,  brings  with  it  the  proportionate 
amount  of  accommodation,  we  have  the  figures  for  the  nerve 
strain  which  would  be  caused  by  such  prism  as  follows : 

Convergence,  L.  50,  R.  50;  automatic  accommodation,  L. 
1.00,  R.  1.00;  total,  3  D.  per  second.  3x60x60x16=172,800 
D.  per  day  of  sixteen  hours. 

In  a  hyperope  of  1.00  D.  the  same  prisms  could  be  used 
to  advantage  because  they  would  save  one-fourth  of  the  ab- 
normal demands,  thus: 

Accommodation  L  1.00,  R  1.00;  auto  convergence  L  .50, 
R  .50;  negative  pull  by  external  recti  to  prevent  convergence, 
L  .50,  R  .50;  total  4.  D.  per  second.  4x60x60x16=230,400  D. 
per  day  of  sixteen  hours. 

The  prisms,  making  the  convergence  a  necessity  while  the 
accommodation  adapts  the  focus,  the  negative  pull  is  not 
needed,  and,  as  it  constitutes  one-fourth  of  the  total  the  prisms 
save  57,600  D.  daily.  But  would  not  a  doctor  be  a  chump  to 
save  that  when  he  could,  with  a  simple  pair  of  +  spheres,  save 
the  whole  230,400? 

Here  is  another  notable  thing :  If  the  prisms  be  prescribed 
in  combination  with  the  sphere  the  effect  would  be  just  the 
same  as  with  the  prisms  alone,  for,  the  prisms  alone  save  57,600 
out  of  the  230,400,  leaving  the  net  strain  172,800,  while  in  the 
combination  the  lenses  would  make  the  eyes  emmetropic  and 
we  have  shown  that  the  strain  on  an  emmetrope  is  172,800. 

Here  is  another:  A  pair  of  -f  .75  lenses  each  ground  in 
combination  with  2°  base  out,  would  be  exactly  neutralized 
therapeutically,  except  the  psychic  effect. 


SOME  PRISM  FIGURES.  J23 

Accommodation,  L.  .75.  R.  .75;  auto  convergence,  L.  .371/2, 
R.  .371/2;  negative  pull  via  sixth  nerves,  L.  .371/2,  R.  .371/2. 
Total,  3.  D.  per  sec.     3x60x60x16^-172,800  D.  daily. 

The  correction  makes  patient  emmetropic  and  saves  the 
above  amount,  but  then  the  prisms  come  in  and  cause: 

Convergence,  L  .50;  R  .50;  automatic  accommodation,  L 
1.00,  R  1.00.  Total,  3.  D.  per  sec.  3x60x60xl6=-172,800  D. 
daily. 

Then  take  a  hyperope  of  1.00  D.  and  correct  the  error,  but 
combine  4°  prism,  base  out,  with  each  lens,  and  the  effect  would 
be :  The  spheres  make  an  emmetrope  and  save  230,400  D.  daily, 
but  the  prisms  cause  two  meter-angles  convergence  and  total 
nerve  strain,  thus: 

Convergence,  L  1.00,  R  1.00;  automatic  accommodation,  L 
2.00,  R  2.00.  Total  6.  D.  per  sec.  6x60x60xl6=-345,600  D. 
daily,  or  exactly  the  equivalent  of  the  strain  caused  by  1.50 
hyperopia.  The  same  result  could  have  been  obtained  with  a 
pair  of  —  .50  spheres. 

Take  a  hyperope  of  3.00  with  a  total  strain  of  691,200  D. 
daily  and  give  him  +  2.00  Q  2°  base  out,  each  eye,  and  the 
lenses  will  save  460,800,  while  che  prisms  save  one-fourth  of  the 
rest  or  57,600,  a  grand  total  of  518,400  out  of  a  possible  691,200 ; 
but  if  +  1.00  had  been  added  to  the  lens  instead  of  the  prigm, 
the  whole  would  have  been  saved. 

Take  the  same  case  and  combine  with  the  -f  2.00  lenses  4' 
prism  each  and  the  effect  will  be  that  the  lenses,  leaving  1.00  D. 
hyperopia  uncorrected,  would  mean  nerve  strain : 

For  accommodation,  L.  1.00,  R.  1.00;  auto-convergence,  L. 
.50,  R.  .50 ;  negative  pull,  L.  .50,  R.  .50.  Total  4.  D.  per  second. 
But  when  the  prisms  get  in  their  work  the  result  is  different. 
They  cause  a  strain  as  follows: 

For  convergence,  L.  1.00,  R.  1.00;  auto-accommodation,  L. 
2.00,  R.  2.00.  Total,  6.  D.  per  second.  There  would  be  some 
benefit  even  from  this  combination  because  the  original  strain, 
from  the  error,  was  12  D.  per  second  and  half  of  it  would  be 
saved;  but  if  the  prisms  were  left  out  two-thirds  would  be 
saved. 


J  24  OPTICAL  TRUTHS. 

The  whole  matter  resolves  itself  into  this:  If  4  base  out 
causes  172,800  D.  daily  strain  on  an  emmetrope,  whether 
naturally  so  or  made  that  way  artificially,  1°  would  cause 
43,200  D.  daily  up  to  the  limit  of  capacity  to  overcome  prism 
degrees,  and  to  find  the  damage  any  amount  of  prism  base 
out  will  do,  multiply  the  above  figure  by  the  strength  of  prism. 
The  reason  prisms  do  not  always  do  harm  is  because  the  doc- 
tor unwittingly  leaves  part  of  the  hyperopia  uncorrected  or 
the  benefit  from  the  spheres  is  so  much  greater  than  the  dam- 
age done  by  the  prisms  that  the  net  result  is  good.  But  neither 
the  prisms  nor  the  doctor  deserves  any  credit. 

We  are  not  yet  able  to  measure  the  exact  strain  when  the 
prism  is  base  in,  but  it  is  a  reasonable  estimate  to  put  it  at 
about  one-fifth  as  much  as  if  base  out,  because  it  bears  on 
the  sixth  nerves,  which  have  no  branches,  while  the  third  have 
five  principal  ones,  therefore  each  degree,  base  in,  would  cause 
8,640  D.  daily  strain,  up  to  the  limit  of  capacity  to  overcome 
them.  Base  up  or  down,  would  bear  on  third  nerves  again 
and  we  estimate  the  strain  at  one-third  as  much  as  if  base  out, 
or  14,400  for  each  l^ 

The  capacity  of  the  intemi  rarely  exceeds  20° ;  that  of  the 
externi  6° ;  that  of  the  superior  and  inferior  recti  3°. 

To  test  the  pulling  powers  of  prisms  within  the  limit,  and 
the  non-pulling  powers  of  those  Which  exceed  the  limit,  take  a 
2°,  hold  it  base  down  in  front  of  one  eye,  both  being  open, 
and  look  at  a  light  several  feet  distant,  when  it  will  appear 
as  two;  fix  on  it  until  it  appears  single,  then  withdraw  the 
prism.  If  it  does  not  pull  when  put  on  it  will  as  it  leaves. 
Then  try  a  10°  in  the  same  manner  and  there  will  be  no  pull 
because  the  job  is  such  a  big  one  there  is  no  effort  to  do  it. 

Possibly  some  eye  doctors  who  have  been  prescribing 
prisms  with  varying  results  will  now  be  able  to  see  why  they 
won  when  they  won  and  why  they  failed  when  they  failed, 
which  was  frequently. 

"But,"  someone  says,  "What  are  you  going  to  do  about 
the  muscles  when  tests  indicate  prisms  are  needed?"     I  deny 


SOME  PRISM  FIGURES.  J25 

there  are  any  such  cases,  with  the  possible  exception  of  a  lack 
of  ability  in  some  old  people  to  converge  or  in  a  myope  who 
tires  at  close  work  or  without  correction,  when  prisms,  bases 
in,  might  be  used  for  reading  only,  in  connection  with  the 
additional  spheres  required  in  the  case  of  the  presbyope  and 
without  lenses  for  the  myope ;  I  never  saw  but  one  person  who 
required  them  even  for  that  purpose.  In  case  of  such  need, 
however,  here  are  the  figures: 

For  1  meter-angle    4°  base  in,  part  in  each  eye. 

For  2  meter-angle    8°  base  in,  part  in  each  eye. 

For  3  meter-angle  12°  base  in,  part  in  each  eye. 

For  4  meter-angle  16°  base  in,  part  in  each  eye. 

For  5  meter-angle  20°  base  in,  part  in  each  eye. 

One  meter-angle  is  40  inches. 

Two  meter-angle  is  20  inches. 

Three  meter-angle  is  13  inches. 

Four  meter-angle  is  10  inches. 

Five  meter-angle  is  8  inches. 


EYE  INSTRUMENTS  AND  MACHINES. 

Saving  the  Ophthalmoscope  the  Remainder  Are  Valuable  Only 

to  Bluffers. 

The  ophthalmoscope  is  easily  the  most  important  objective 
instrument  used  in  examinations  of  cases,  but  few  realize  the 
fact  as  is  proved  by  the  manner  in  which  they  use  it.  The 
indirect  method  of  observation  consists  of  throwing  light  into 
the  eye  from  a  point  ten  or  twelve  inches  away  and  interpos- 
ing a  strong  +  sphere;  this  may  be  imposing  in  appearance 
but  it  is  mostly  humbug  on  the  part  of  the  operator  because 
he  can  not  hold  all  the  points  necessary  to  be  in  line  to  see 
anything  of  the  retina  and  when  he  is  able  to  do  it  he  only  gets 
an  inverted  aerial  image.  If  one  insists  upon  that  method  he 
should  get  one  of  my  instruments,  Fig.  61,  because  it  keeps 
all  points  in  line  and  gives  the  best  results  possible  indirectly. 
It  is  comparatively  inexpensive,  is  portable,  weighs  only  seven 
pounds  and  is  lighted  directly  instead  of  by  mirrors. 

The  best  method  is  the  direct  one,  because  the  operator 
sees  the  retina  instead  of  its  picture,  and  sees  it  upright  instead 
of  reversed,  besides  the  facilities  it  affords  for  exploring  parts 
not  possible  by  the  indirect  method.  The  Loring,  nineteen-lens 
instrument.  Fig.  62,  is  the  best  because  it  is  simplest.  It  com- 
prises in  one  disk  fifteen  lenses,  from  1.  D.  to  7  D.  J-  and 
from  1.  D.  to  8.  D.  — ;  then  a  second  disk  carries  four  lenses 
^50.  and  +  16  D.  and  —  .50  and  —  16.  D.  If  more  than  the 
highest  number  in  the  lower  disk  is  wanted  turn  on  the  16.  D., 
j^  or  — ,  then  rotate  the  under  disk  until  the  desired  number 
shows.  A  +  16.  on  +  7.  would  register  4^  23.  of  course,  but 
by  rotating  the  lower  disk  the  +  7.  is  displaced  and  —  8.  is 
combined  with  the  +  16.  giving  +  8.,  then  further  rotation 
brings  it  on  up  to  4-  16.  and  still  more  turning  add  +  1.,  2.,  3., 
etc.,  ur)  to  23.  D.  again.  The  —  works  in  the  same  manner,  up 
to  24.  D. 

Books  on  the  use  of  the  ophthalmoscope  are  misleading  in 


128 


OPTICAL   TRUTHS. 


two  important  directions:  First,  many  of  them  convey  the 
idea,  either  directly  or  indirectly,  that  the  authors  measure 
errors  of  refraction  with  it,  which  is  an  impossibility,  because 
not  only  the  patient  but  the  operator  would  have  to  be 
atropized  so  thoroughly  that  neither  could  work  the  accom- 
modation, and  were  that  possible,  the  skill  required  to  get  the 
same  focus  on  the  vertical  and  horizontal  vessels,  the  vertical 


Fig.   62 


EYE  INSTRUMENTS  AND  MACHINES.  J  29 

being  much  larger,  would  be  impossible  of  attainment;  hence 
such  claims  are  either  foolish  or  deliberate  lies.  Second,  they 
illustrate  diseases  and  alleged  diseases  and  the  student  aban- 
dons the  instrument  because  he  finds  nothing  to  correspond 
with  the  pictures.  The  real  value  of  the  ophthalmoscope  lies 
in  the  facility  it  affords  for  the  study  of  the  quality  and  quan- 
tity of  the  blood  in  every  case.  It  is  of  little  value  to  the 
oculist  because  he  is  strictly  an  eye  doctor,  and  has  no  idea 
of  the  relation  of  the  eyes  to  general  ills.  When  the  general 
practitioner  learns  what  he  should  there  will  be  nothing  left 
for  the  oculist  or  optician,  while  the  ophthalmologist  will  al- 
ways be  in  demand  because  of  his  drugless  creed  and  general 
utility. 

The  things  to  learn  about  ophthalmoscopic  practice  are: 
First,  how  to  place  the  patient;  second,  how  to  get  the  best 
yiew  of  the  fundus ;  third,  what  are  the  variety  of  appearances 
of  the  normal  retina;  fourth,  how  to  differentiate  between 
physiological  freaks  and  true  pathological  conditions ;  fifth,  the 
relation  between  exhibits  and  causes;  sixth,  what  to  do  for 
them. 

The  patient  should  be  seated  comfortably  and  look  straight 
ahead.  The  optic  disk  is  always  the  chief  objective  point  and 
as  it  is  located  about  fifteen  degrees  from  the  posterior  pole, 
on  the  nasal  side,  the  operator  must  throw  light  into  the  pupil 
from  a  point  about  the  same  distance  on  the  temporal  side; 
the  light,  if  a  mirror  without  electric  attachment  is  used, 
should  be  about  two  feet  behind  the  patient  and  far  enough 
on  the  side  so  that  it  will  shine  past  the  edge  of  the  orbit  to 
the  mirror,  leaving  the  eye  in  the  shadow.  If  the  luminous 
instrument  is  used  it  is  easier  to  get  light  into  the  eye,  but, 
on  account  of  an  awkward  crook  in  the  handle  to  make  room 
for  the  small  electric  globe,  it  is  not  so  convenient  in  making 
wide  explorations.  The  light,  the  patient  and  the  operator 
must  be  on  the  same  plane,  which  may  be  either  horizontal  or 
oblique;  if  oblique,  and  the  operator  is  shorter  than  the  pa- 
tient, the  light  must  be  higher ;  if  he  is  taller  than  the  patient, 


130  OPTICAL  TRUTHS. 

the  light  must  be  lower;  if  on  a  level,  the  light  must  corre- 
spond. If  the  first  attempt  fails  to  give  a  good  view,  try 
again.  A  good  guide  is  to  imagine  the  patient  has  two  eyes  in 
the  back  of  his  head,  and  if  looking  into  the  right,  aim  so  the 
light  would  pass  through  the  middle  head  and  out  through  the 
imaginary  right  eye  on  the  opposite  side  of  the  head.  If  the 
blood-vessels  are  seen,  but  not  clearly,  twist  the  handle  of  the 
instrument  a  trifle  so  as  to  change  the  direction  of  the  light; 
if  the  disk  and  vessels  are  seen,  but  dimly,  turn  on  —  spheres 
to  offset  the  operator's  accommodation.  Unless  the  operator 
has  much  astigmatism  it  is  best  to  work  without  glasses  be- 
cause the  need  can  be  supplied  from  the  battery  of  lenses  in  the 
instrument.  Learn  to  use  either  eye,  allowing  the  other  to 
remain  open.  Do  not  twist  the  neck ;  sit  erect,  except  that  it  is 
necessary  to  lean  forward  slightly.  The  back  of  the  opera- 
tor's  chair  should  be  even  with  the  front  of  that  occupied  by 
the  patient.  A  piano  stool  or  other  adjustable  chair  is  con- 
venient. 

Fig.  63  shows  an  average  normal  retina,  except  that  the 
veins,  the  darkest  lines,  are  a  little  too  dark;  there  should  be  a 
faint  light  streak  in  them,  as  shown  in  the  arteries,  represented 
by  the  lighter  lines,  which  are  a  trifle  too  light.  The  white  spot 
in  the  center  is  the  optic  disk,  or  blind  spot,  where  the  retinal 
arteries  ?ind  nerves  enter  and  the  veins  leave  the  globe;  the 
solid  field  shows  the  capillary  system,  which,  combined  with 
the  nerve  branches  by  delicate  connective  tissue,  constitute  the 
retina  which  extends  from  the  edge  of  the  disk  forward  to 
the  edge  of  the  ciliary  body.  The  vessels  should  be  of  regular 
sizes,  gradually  smaller  toward  the  periphery  as  they  divide 
into  branches.  The  currents  of  the  arteries  are  from  the  disk 
and  those  of  the  veins  toward  it.  Examination  of  a  dozen  or 
two  pairs  of  eyes  of  healthy  persons  will  give  the  student  a  bet- 
ter idea  of  what  the  average  condition  is  than  a  whole  volume 
of  pictures  could  do.  He  will  discover  that  in  healthy  chil- 
dren the  contents  of  the  arteries  and  veins  is  so  nearly  the  same 
color  that  it  would  be  difficult  to  distinguish  them  were  it  not 


EYE  INSTRUMENTS  AND  MACHINES. 


131 


for  the  extra  size  of  the  veins ;  while  in  youth  and  middle  age 
the  difference  is  marked,  and  in  old  people  quite  decidedly  so, 
partly  because  of  diminution  in  the  arterial  supply  and  partly 
because  of  lack  of  tension  in  the  walls  of  vessels  which  per- 
mits them  to  flatten  under  the  pressure  of  the  vitreous  humor 
against  them.    In  brunettes  the  blood  is  usually  darker  than  in 


't^iji*'^-' 


Fig-.   «3 


132 


OPTICAL   TRUTHS. 


blondes.  There  may  be  deposits  of  pigment  partly  or  all 
around  the  edge  of  the  disk ;  or  there  may  be  great  patches  of 
pigment  or  even  a  deposit  as  white  and  shiny  as  the  sclerotic, 
without  inflammation,  interference  with  the  vascular  system,^ 
or  diminution  of  vision.  The  number  of  visible  vessels  varies 
from  six  to  as  high  as  thirteen.  The  vessels  may  not  come  so 
near  to  each  other  in  the  center  of  the  disk  as  shown  in  Fig. 
63  and  some  may  disappear  at  the  edge  of  the  disk  as  shown  in 
Fig.  64.  These  appearances  are  caused  by  a  cupping  of  the 
disk  and  have  no  particular  significance.    Fig.  64  was  drawn 


/ 


Fig.   64 


EYE  INSTRUMENTS  AND  MACHINES. 


i33 


from  an  eye  alleged  to  be  glaucomatous,  but  +  2.50  lenses  re- 
moved all  the  other  symptoms  and  the  patient  is  still  happy 
after  nine  years.  The  fairy  stories  about  glaucoma,  its  causes 
and  cures,  are  enough  to  make  angels  weep.  One  writer  de- 
clared he  caused  it  in  one  week  with  atropine  and  cured  it  the 
next  week  with  eserine.  A  reputable  ophthalmic  paper  printed 
the  story  too. 

If  there  are  several  diopters  of  astigmatism  the  disk  may 
appear  blurred  in  one  meridian  but  clear  in  the  opposite  one, 
when  turning  the  lenses  of  the  instrument  will  reverse  the 
appearance. 

Retinitis  begins  at  the  edge  of  the  disk  so  far  as  appear- 
ance goes  and  is  sometimes  so  intense  as  to  obscure  the  edge  as 
shown  in  Fig.  65,  which  also  shows  the  choking  of  the  ves- 
sels often  associated  with  dysmenorrhoea. 


Fig-.   65 


J34 


OPTICAL  TRUTHS. 


In  advanced  stages  of  Bright 's  disease  there  will  be  found, 
in  addition  to  the  diffuse  inflammation,  first  small  pus-patches 
followed  by  a  dry,  white  appearance  (Fig.  66),  which  in  turn 
is  succeeded  by  black  patches  (Fig.  67),  due  to  disintegration 
of  retinal  tissue  exposing  the  pigment;  in  the  last  stage  all 
three  exhibits  are  present. 

In  sjrphilitic  retinal  affections  there  are  black  fantastic 
figures,  like  spider  webs,  fern  leaves  or  ink  splashes,  with  no 
inflammation  unless  there  chances  to  be  kidney  trouble,  which 
is  rare. 

Obstructions  in  vessels  show  congestion  as  in  Fi^.  68. 
Pressure  is  liable  to  rupture  the  vessels  when  the  extravasated 
blood  would  spread  out  and  coagulate,  at  least  temporarily 
destroying  vision.  In  time,  however,  reabsorption  may  occur 
and  vision  be  restored. 


4 


Fig.  66 


EYE  INSTRUMENTS  AND  MACHINES. 


135 


In  chlorosis,  although  the  cheeks  nsay  be  rosy,  the  internal 
view  discloses  pale  arteries  and  dark  veins,  with  a  lack  of 
quantity  in  both.  Such  cases  complain  of  general  tired  feel- 
ings and  confess  to  attacks  of  faintness. 

Dark  arterial  blood  means  the  liver  is  not  working,  and 
even  when  the  arteries  are  pretty  good  color,  if  the  veins  are 
unusually  dark,  look  for  a  coated  tongue. 

Be  sure  to  look  for  the  "yellow  spot  of  Soemmering,"  in 
every  case.  If  you  find  it,  I  am  a  liar.  If  you  don't  find  it, 
Soemmering  and  his  tribe  are.  The  posterior  pole  has  a  field 
around  it  upon  which  images  must  be  formed  to  be  seen 
clearly,  but  there  is  no  more  color  to  it  than  there  is  to  any 
of  the  other  parts.  It  is  more  free  from  large  vessels,  but 
there  is  no  other  distinguishing  feature.  Some  other  German 
professor  should  come  along  and  tell  us  he  sees  the  pole. 


riff   bi 


136 


OPTICAL  TRUTHS. 


Do  not  take  anyone's  word  for  anything  except  where  it 
is  exclusively  a  matter  of  veracity — and  go  slow  on  that. 
Learn  by  practice  what  constitutes  a  normal  retina,  and  when 
there  is  departure,  you  will  know  it  without  pictures  as  guides. 

Retinascopy,  skiascopy,  skiametry,  pupiloscopy,  koroscopy, 
and  the  shadow  test,  are  synonymous.  It  is  an  objective 
method.  While  they  work  well  on  schematic  eyes,  which  are 
fixed  dioptric  systems,  it  is  a  physiological  impossibility  for 
them  to  be  used  with  any  degree  of  accuracy  in  fitting 
glasses,  because  the  intense  light  thrown  in  the  eyes  sets  the 
accommodation  and  iris  to  work  at  once,  the  pupil  becomes 


Fig.   63 


EYE  INSTRUMENTS  AND  MACHINES. 


137 


smaller  and  the  dioptric  system  is  changed  decidedly,  decreas- 
ing hyperopia,  increasing  myopia  and  making  emmetropia 
myopia. 


Pig-.    69 

Fig.  69  will  be  of  service  in  explaining  the  action  of  the 
principle.  The  three  lines  crossing  the  axis  at  A  represent 
three  positions  of  the  mirror.  Fig.  70  is  a  mirror,  it  being  in 
this  instance  a  plane  one.  The  light  being  reflected  from  the 
morror  M'  at  A  Fig.  69  would  focus  at  B  if  it  could  get  there, 
but  as  the  retina  is  in  the  way  there  are  circles  of  diffusion 
formed  at  V  and  the  light  comes  back  from  those  circles  over 
the  lines  upon  which  it  entered,  also  along  the  dotted  lines  0 
and  X  and  in  all  the  space  between  them,  so  that  the  entire 
pupil  is  illuminated.  By  tilting  the  mirror  back  to  M-  the 
dotted  line  0  becomes  the  line  V  A,  and  the  original  line,  with 
all  the  rest,  drops  below  the  axis  at  the  peep-hole  so  the  only 
illumination  comes  from  the  upper  part  of  the  pupil,  the  rest 
being  in  eclipse — this  is  the  shadow  that  follows  the  move- 
ment of  the  mirror  in  hyperopia,  emmetropia  and  myopia  of 
less  amount  than  the  equivalent  of  the  working  distance.  If 
the  mirror  be  tilted  to  the  position  M'  the  line  X  will  become 
the  line  B  A,  and  all  the  rest  will  be  above  the  axis  at  the 
peep-hole.  The  +  lens  which  will  bring  the  dotted  lines  down 
the  black  lines'  course  to  A  is  the  measure  of  the  defect  plus 


J38 


OPTICAL   TRUTHS. 


the  working  distance.  The  light  may  be  thrown  across  the 
pupil  vertically,  horizontally  or  obliquely,  and  if  the  shadow 
moves  with  the  operator's  movement  of  the  mirror  +  lenses 
will  be  required.  If  too  much  is  put  on  it  will  cause  the  move- 
ment of  the  shadow  to  be  against  the  mirror  movement  because 
the  rays  0  and  X  will  cross  before  they  reach  the  peep-hole. 


'W^  'h^'yy\i 


Fig.   71 


Fig.  71  shows  how  the  same  mirror  works  on  highly 
myopic  eyes.  The  rays  reflected  from  the  mirror  M^  at  A 
focus  at  B,  and  form  circles  of  diffusion  at  the  retina.    The 


EYE  INSTRUMENTS  AND  MACHINES. 


139 


rays  return  along  the  black  lines,  the  dotted  lines,  and  from  all 
the  space  between  the  black  lines  at  the  retina  to  all  space  be- 
tween the  dotted  lines  at  the  mirror.  Tilting  the  mirror  to 
M-  raises  the  illuminated  field  at  the  retina  and  lowers  the 
field  at  the  mirror  so  that  the  ray  0  falls  into  the  peep-hole 
while  the  rest  drop  below,  but  as  this  ray  comes  from  the  lower 
part  of  the  pupil,  which  is  the  illuminated  portion,  the  shadow 
movement  is  against  the  mirror.  Tilt  the  mirror  to  M^^  and  all 
the  rays  returning  to  the  mirror  will  rise  and  X  will  fall  into 
the  peep-hole,  the  shadow  will  move  up  as  the  light  is  turned 
downward  at  the  eye.  The  —  lens  which  will  cause  the  dotted 
lines  to  diverge  until  they  only  meet  at  the  peep-hole  will  be 
the  correction,  minus  the  working  distance.  After  finding  the 
lens  which  stops  the  shadow,  or  in  other  words  brings  the  ob- 
served retina  in  conjugate  focus  with  the  observer's,  if  the 
lenses  are  +  they  must  be  reduced  the  equivalent  of  the  work- 
ing distance  and  if  —  they  must  be  increased  that  amount. 
That  is,  if  the  working  distance  is  20  inches  the  -{-  lenses  will 
be  2.00  D.  too  strong,  and  the  —  lenses  will  be  2.00  D.  too 
weak.  If  the  +  lenses  are  less  than  2.00  D.  the  eye  is  myopic 
the  amount  of  the  difference  between  the  power  of  the  lens 
and  2.00.  Or,  again,  after  getting  the  correction,  -(-  or  — . 
hold  a  —  sphere  equal  to  the  working  distance,  in  front  of  the 
lens  or  combination,  to  give  good  distant  vision. 

U 


Fig.   72 


140 


OPTICAL   TRUTHS. 


If  the  concave  mirror  is  used  the  efTects  will  be  reversed, 
the  shadow  will  move  against  the  mirror  movement  in  hy- 
peropia, emmetropia  and  in  myopia  less  than  the  working"  dis- 
tance. Fig.  72  will  give  a  pretty  clear  idea  of  how  the  light 
gets  into  and  out  of  the  eye  by  this  method.  It  is  decidedly 
more  complicated  than  with  the  plane  mirror,  but  the  result  is 
the  same  because  it  is  the  light  coming  out  that  the  operator 
has  to  deal  with.  Rays  from  the  light  L,  to  the  mirror  are 
reflected  to  the  point  I  where  an  image  is  formed  which  be- 
comes the  real  light  so  far  as  the  eye  is  concerned,  the  rays 
from  which  would  focus  at  B,  if  they  could  get  there,  but  they 
form  circles  of  diffusion  from  C  to  C  and  the  light  is  reflected 
as  shown  from  lower  C  along  the  dotted  lines  1-2,  and  from 
upper  C  along  the  dotted  lines  3-4.  It  will  be  seen  that  with 
the  light  I  below  the  axis  the  circles  of  diff'usion  between  C-0 
will  be  above  the  axis  and  all  the  light  that  strikes  the  peep- 
hole in  the  mirror  must  come  from  the  vicinity  of  lower  C  and 
follow  dotted  lines  1  and  3  and  all  in  the  space  between.  Turn- 
ing the  mirror  so  that  the  light  I  is  above  the  axis  will  put  the 
circles  C-C  below  and  the  rays  from  C-C  at  their  new  position 


Fir.  73 


EYE  INSTRUMENTS  AND  MACHINES. 


141 


will  follow  the  dotted  lines  2  and  4  and  all  in  the  space  between 
as  they  are  raised  toward  the  peep-hole.  Of  course  the  shadow 
in  on  the  opposite  side ;  and,  as  shown  in  the  cut,  the  shadow 
comes  up  as  the  mirror  is  turned  down. 

If  the  eye  is  highly  myopic  a  new  feature  presents  itself. 
The  mirror  forms  an  image  in  front  of  the  eye,  the  dioptric 
system  forms  an  image  of  the  first  one,  which  has  become  the 
real  light  to  it,  then  the  rays  pass  back  to  the  retina  and  form 
circles  between  C-C.  (Fig.  73.)  The  dotted  lines  1-2  and  3-4 
show  the  course  of  the  emergent  rays.  In  the  position  shown 
the  mirror  is  throwing  the  light  just  below  the  axis  and  the 
image  in  the  eye  is  just  above  the  axis ;  the  light  that  gets  in 
the  peep-hole  follows  the  line  4-4-4,  hence  the  illumination  is 
below  and  the  shadow  moves  with  the  mirror  movement.  Turn 
the  mirror  up  so  it  forms  the  image  above  the  axis,  the  one 
in  the  eye  will  be  below,  the  circles  will  drop  down  and  the 
illumination  will  follow  the  line  1-1  which  will  then  be  in  the 
same  position  above  the  axis  that  4  is  below,  as  shown  in  cut, 
thus  the  illumination  will  come  from  the  upper  part  of  the 
pupil  and  the  shadow  follow  from  below,  with  the  mirror 
movement. 

I  have  given  space  to  this  story  because  it  has  never  been 
told  in  detail  before.    As  a  means  of  measuring  errors  of  re- 


Fig.  74 


J42  OPTICAL   TRUTHS. 

fraction  retinascopy  is  worthless  on  account  of  the  physiolog- 
ical obstacles  mentioned  in  the  beginning.  When  anyone  says 
he  can  fit  eyes  by  the  method  he  is  a  humbug,  and  the  worst  of 
it  is,  he  humbugs  himself. 

The  prisoptometer,  Fig.  74,  is  a  subjective  method  of  at- 
tempting to  measure  errors,  but  it  is  very  unreliable,  for  two 
reasons :  First,  the  operator  is  compelled  to  rely  on  what  the 
patient  tells  him,  with  reference  to  the  targets;  second,  the 
test  is  a  monocular  one  and  there  is  a  constant  tendency  to 
induce  rather  than  suspend  accommodation. 

The  ophthalmometer.  Fig.  75,  is  an  objective  test  and  is 
an  imposing  appearing  instrument  to  those  who  are  in  awe  of 
apparatus,  but  it  attempts  a  geometric  impossibility  in  its  prin- 
ciple, proposing,  with  a  fixed  spherical  curvature  in  itself,  to 
measure  a  variety  of  spherical  and  ellipsoidal  curvatures  in 
others.  Its  makers  only  claim  it  will  register  the  axis  exactly 
and  approximate  the  amount  of  astigmatism.  When  one  con- 
siders the  fact  that  oblique  astigmatism  is  sometimes  exhibited 
by  spasm  or  exhaustion  of  the  nerve  supply  to  the  oblique 


EYE  INSTRUMENTS  AND  MACHINES.  t43 

muscles ;  that  approximates  to  the  amounts  of  astigmatism  are 
not  what  a  good  doctor  is  looking  for;  that  all  work  done  by- 
it  has  to  be  done  over  by  subjective  methods;  that  it  is  ex- 
pensive and  that  it  is  monocular,  the  conclusion  is  reached 
quickly  that  the  price  of  it  would  be  better  employed  in  some 
other  manner. 

The  stigmatometer  is  both  an  objective  and  subjective  in- 
strument, it  embodies  many  excellent  physical  principles,  and 
is  a  compliment  to  its  young  inventor.  The  only  faults  I  find 
with  it  are:  First,  it  is  monocular;  second,  it  is  expensive; 
third,  it  is  not  practical  for  many  of  the  same  reasons  other 
machines  are  not.  It  may  do  for  opticians  or  oculists,  but 
neurologists  and  ophthalmologists,  who  are  worthy  of  the 
name,  have  no  use  for  such  things,  as  they  take  valuable  time 
that  can  be  devoted  to  more  effective  methods  which  only  cost 
money  as  education  is  paid  for. 

Phorometers,  optometers,  refractometers,  and  all  similar 
devices  are  worth  more  to  the  makers  and  sellers  than  to 
anyone  else. 

The  perimeter  is  all  right  in  a  school  room  or  for  experi- 
mental purposes,  but  in  the  doctor's  office  it  is  of  less  value 
than  a  retinascope. 

A  good  platform  scale  is  worth  more  than  a  cart-load  of 
the  instruments  enumerated  after  the  ophthalmoscope,  which 
is  really  a  necessity. 


ABOUT  ALLEGED  EYE  DISEASES. 

Suggestions  for  Simple,  Rational  Procedure  Instead  of  the 
Old-School  Frenzied  Methods. 

When  we  talk  from  the  standpoint  of  the  old  schools,  we 
should  call  everything  disease  except  emmetropia.  Hyperopia 
would  be  a  disease  because  it  produces  discomfort.  Right  here 
we  have  one  of  the  greatest  proofs  that  the  old  schools  lack 
method  and  foundation,  because  if  disease  is  the  cause  of 
troubles,  the  inflammations,  hypertrophies,  paralyses,  and 
atrophies  produced  by  the  efforts  to  overcome  hyperopia,  which 
are  treated  by  them  as  original  diseases,  benign,  malignant, 
contagious,  or  infectious,  are  merely  the  effects  of  diseases, 
therefore  not  the  causes. 

Hyperopia  is  a  simple  lack  of  development  of  the  visual 
organs,  and  it  is  no  more  uncommon  than  the  lack  of  develop- 
ment of  the  nose-bridge;  the  reason  it  causes  more  trouble  is 
the  existence  of  a  mechanism  by  which  it  can  be  overcome 
largely,  therefore  hyperopia  makes  necessary  nervous  activity 
in  excess  of  normal,  and  as  the  daily  amperage  is  increased 
from  1,000,000  units  23  per  cent,  for  each  unit  of  hyperopia,  it 
means  that  to  sustain  this  extra  amount  a  greater  voltage  has 
to  be  turned  on  from  the  cerebellum,  and,  as  that  voltage  can- 
not be  applied  to  the  eyes  alone,  it  necessarily  involves  the  en- 
tire system,  which  is  practically  on  one  circuit,  and  it  becomes 
easier  to  short-circuit  a  high  voltage;  even  if  it  is  not  short- 
circuited,  it  will  increase  the  temperature  throughout,  partic- 
ularly in  the  end  organs,  that  is,  where  the  sphincter  muscles 
are  located.  Then  follows  congestion  of  blood  vessels,  particu- 
larly in  those  regions,  and  we  have  external  and  internal  in- 
flammations, the  former  being  more  alarming  to  the  laity  and 
ignorant  doctors  because  it  looks  fierce,  and  because  it  has 
the  additional  irritation  from  atmospheric  changes  and  from 
maltreatment  by  the  patient,  who  rubs  it,  or  scratches,  or  ap- 


146  OPTICAL   TRUTHS. 

plies  remedies  suggested  by  "buttinskies;"  the  internal  effects 
are  certainly  the  worst,  because,  although  protected  from  the 
secondary  disturbers,  described  above,  they  are  for  the  same 
reason  less  liable  to  occur  from  the  original  cause  alone,  hence 
when  they  do  occur,  the  situation  is  more  serious.  Our  treat- 
ment is  practically  the  same  for  both,  part  of  which  is  to  re- 
quire the  patient  to  stay  indoors,  to  avoid  in  the  first  case  the 
atmospheric  changes,  and  in  the  second  case,  to  prevent  con- 
tinued use  of  the  machinery  which  is  producing  such  bad  re- 
sult;:. 

Of  course,  for  the  external  troubles,  we  apply  cold  salt 
water  compresses  to  antiseptisize  and  reduce  the  temperature; 
but  it  is  our  internal  chemical  treatment  through  dieting,  the 
mechanical  manipulation  and  the  glasses  which  correct  the 
hyperopia  that  remove  all  the  effects.  For  the  internal  effects, 
which  we  know  are  by  far  the  most  serious,  if  there  is  pain, 
we  apply  hot  water  compresses  sometimes  alternating  with 
cold,  if  the  hot  does  not  give  relief  pretty  quickly  and  if  the 
pupil  is  small  it  does  no  harm  to  dilate  it  with  atropine  and 
may  prevent  adhesion  of  the  iris  and  lens.  It  has  no  effect  on 
the  cause  but  merely  dilates  the  pupil,  to  make  it  clear  the 
apex  of  the  lens. 

In  order  to  differentiate  external  and  internal  eye  troubles 
take  the  following  symptoms  and  what  they  mean : 

External — Looks  badly.  Is  not  dangerous  unless  neg- 
lected. Does  not  impair  vision.  Is  not  painful.  Appearance 
sometimes  causes  nausea,  when  patient  sees  it  in  mirror.  Is 
sometimes  itchy  or  smarts.  Hypertrophy  or  pterygium  or 
pannus  may  result.    Does  not  affect  accommodation. 

Internal — Does  not  look  badly.  Is  dangerous.  Affects 
vision,  because  retina  is  influenced.  Is  painful  from  ciliary 
cramps.  Does  not  nauseate.  Does  not  itch  or  smart.  No  such 
thing  as  hypertrophy  is  possible.  Always  affects  accommo- 
dation. 

Double  symptoms  mean  both. 

Retinitis  is  not  always  discoverable  with  the  ophthalmo- 


ABOUT  ALLEGED  EYE  DISEASES  147 

scope,  therefore  when  it  is  thus  seen,  it  has  reached  a  serious 
stage  and  no  patient  should  be  allowed  to  use  the  eyes  while 
that  symptom  is  present.  Any  unusual  sensitiveness  of  the 
retina,  except  that  indicated  by  keen  vision,  indicates  retinitis. 
There  are  two  kinds  of  that  seen  by  the  ophthalmoscope.  First, 
that  which  begins  at  the  edge  of  the  disk ;  second,  that  caused 
by  congestion  of  the  choroidal  vessels,  thus  putting  pressure  on 
retinal  vessels  at  certain  places,  which  will  exhibit  themselves 
by  retinitis,  with  a  center  of  its  own  independent  of  the  disk, 
marked  by  a  little  blood  clot.  This  is  the  wonderful  ' '  choroidic- 
retinitis."  What  is  known  as  neuro-retinitis  or  choked-disk  is 
only  found  in  females  with  amenorrhoea  or  dysmenorrhea,  or, 
in  other  words,  tonic  spasm  of  the  sphincter  system,  in  at  least 
98  per  cent,  of  the  cases.  The  primary  cause  is  hyperopia,  but 
the  general  involvement  of  the  entire  system  puts  it  beyond 
the  power  of  the  eye  correction  to  cure ;  however  even  the  op- 
tician who  has  sense  enough  to  fog  vision  with  plus  lenses  will 
do  absolutely  no  harm  and  infinitely  more  good  than  the  old 
school  physician  or  surgeon,  with  their  drugs  and  knives. 
Their  criminal  ignorance  of  physics  and  dietetics,  manual 
treatments,  etc.,  are  an  indelible  blot  on  the  American  Asso- 
ciation of  Medical  Colleges,  whose  product  have  removed 
ovaries  in  their  endeavors  to  relieve  effects  of  what  was  really 
nothing  but  ulcerated  teeth ;  who  have  castrated  thousands  of 
women  to  relieve  effects  that  were  really  caused  by  hyperopia. 
The  proof  lies  in  two  facts,  first,  their  own  records  show  they 
have  uniformly  failed;  second,  hundreds  of  graduates  in 
neurology  and  ophthalmology  have  not  only  procured  the  cure 
of  all  cases  not  operated  or  doped,  and  have  relieved  almost 
completely  nearly  all  of  those  who  came  to  them  after  having 
survived  the  operations  and  doping.  This  particular  neuritis 
exhibits  an  intense  inflammation  around  the  disk,  so  that  the 
edge  is  obscured  by  the  congestion.  The  arteries  will  be  prac- 
tically empty  and  the  veins  very  much  congested,  both  be- 
cause of  the  cramp  around  the  optic  nerve  entrance  which  is 
also  the  entrance  of  the  retinal  branches  of  the  ophthalmic 
artery  and  the  exit  of  the  branches  of  the  ophthalmic  vein. 


J  48  OPTICAL   TRUTHS. 

A  retinitis  that  is  frequently  found  in  both  males  and 
females,  but  more  frequently  in  the  former,  is  somewhat  simi- 
lar to  the  above  described,  with  the  exception  that  there  is  no 
emptying  of  the  arteries,  rarely  congestion  of  the  veins  to  the 
extent  of  thrombolism  or  embolism  (the  result  of  plugging) 
and  the  inflammation  around  the  disk  is  more  widespread.  It 
has  been  called  albuminuric  retinitis,  meaning  incipient 
Bright 's  disease,  and  if  allowed  to  continue,  the  disorder  in- 
creases, eventually  exhibiting  yellowish  patches  to  be  followed 
at  the  next  stage  by  white  ones  and  finally  by  black  ones;  of 
course  when  the  black  appear  in  one  part,  another  may  exhibit 
white,  another  yellow  patches,  and  the  rest  simple  inflamma- 
tion; but  we  know  by  the  exhibit  the  stage  of  progress  of  the 
so-called  disease.  The  alleged  oculist  who  examines  by  the 
indirect  method  would  never  see  these  things  because  he  could 
not;  the  direct  method  is  as  superior  to  the  indirect  as  truth 
is  to  falsehood,  or  as  a  person  is  to  his  picture.  Here  is  where 
the  neurologist  is  so  far  ahead  of  general  practitioner  and 
oculist,  that  there  is  no  comparison,  neither  of  these  doctors  is 
competent  to  recognize  the  disease  so  soon,  and  neither  is  com- 
petent to  treat  it  in  a  simple  effective  manner,  because  they 
labor  under  the  impression  it  is  a  kidney  disease,  when  if  we 
were  going  to  call  it  a  disease  at  all,  we  would  be  compelled 
to  say  it  was  a  liver  disease,  for  the  kidneys  cannot  possibly 
suffer  if  the  liver  is  performing  its  functions  normally ;  but  we 
cannot  call  it  a  liver  disease,  because  the  liver  disturbance  is  al- 
ways produced  by  being  overloaded,  from  the  portal  circu^^ation, 
which  comes  from  the  stomach,  spleen,  mesenteries  and  intes- 
tines, in  other  words  the  digestive  apparatus ;  we  cannot  call 
it  a  disease  thereof,  because  this  apparatus  was  compelled  to 
handle  the  food  that  was  put  in  it ;  we  cannot  call  it  a  disease 
of  the  food — because  nature  combined  the  elements  in  proper 
order,  hence  the  fault  was  from  the  patient,  in  his  ignorance, 
putting  into  the  apparatus  a  wrong  quantity  or  a  wrong  com- 
bination of  chemical  elements,  thus  producing  all  of  the  dis- 
orders.    Thus  we  might  prove  from  one  standpoint  that  all 


ABOUT  ALLEGED  EYE  DISEASES.  149 

diseases  are  mental,  and  that  all  cures  must  be  mental,  that  is, 
remedy  the  ignorance  and  the  administration  of  functions  will 
be  consistent  with  nature.  On  the  other  hand,  we  explode  the 
faith  cure,  the  suggestion  idea,  the  dope  feature,  and  all  the 
mysterious  humbug  theories  extant,  because  we  see  the  faith 
healers  and  their  votaries  sicken  and  die;  we  see  the  chief 
exponent  of  suggestive  therapeutics  lose  his  wife  by  suicide; 
we  see  the  dope  doctors  put  in  kidney  remedies,  and  ignore  the 
liver;  we  see  the  mysterious  practitioner  make  himself  ridicu- 
lous by  his  glaring  ignorance. 

Neurology  teaches  we  must  make  no  claims  that  we  cannot 
establish  beyond  question,  it  teaches  there  is  a  limit  angle  not 
only  to  what  men  can  do,  in  the  way  of  assisting  nature  to 
restore  health,  but  there  is  also  a  limit-angle  to  Nature's  ca- 
pacity, and  when  it  is  passed  she  goes  down  to  the  death  of 
the  patient,  which  is  as  natural  as  for  her  to  go  the  other  way 
when  the  case  is  within  the  limit  angle  of  human  assistance; 
therefore  when  a  patient  recovers  under  our  ministrations  we 
congratulate  ourselves  that  we  did  not  hamper  Nature  and  that 
we  rendered  only  such  assistance  as  we  knew  positively,  math- 
ematically, would  assist  her  and  we  ascribe  all  the  credit  to 
Nature  for  making  such  laws  and  permitting  us  to  discover  as 
much  as  we  have,  and  to  the  patient  for  exhibiting  sense 
enough  to  follow  instruction  strictly,  thus  insuring  the  greatest 
possible  benefits  without  any  probable  interference  with  nature. 
We  have  learned  that  when  the  second,  third  and  fourth  stages 
are  reached  the  case  has  increased  in  malignancy  in  the  ratio 
that  the  figures  bear  to  one — for  instance : 

1 — Simple  inflammation. 

2 — Yellow  spots. 

3 — Yellow  and  white. 

4 — Yellow,  white  and  black  spots. 

There  are  always  at  least  two  effects  from  any  disorder  of 
the  machinery,  the  one  described  above  is  the  product  of  chemi- 
cal poisoning.  Another  is  the  clogging  of  the  machinery,  so 
that  its  functions  stop  entirely ;  for  example,  the  accumulations 


J50  OPTICAL   TRUTHS. 

of  sugar  in  the  liver  interfere  with  its  working  and  much  of  it 
passes  on  to  the  kidneys,  clogging  them  also.  At  first  there 
may  be  polyuria  succeeded  by  the  desire  to  void  urine,  but 
inability  to  do  so  on  account  of  the  sugar  deposits.  When  it 
reaches  this  stage  it  kills  quickly,  on  the  same  principle  that 
one  chokes  to  death.  The  eye  indications  are  objective  and 
subjective,  the  patient  will  complain  of  floating  specks 
(muscae  volitantes) ;  with  the  ophthalmoscope  we  see  a  dappled 
or  greenish  streaked  appearance  of  the  retina  with  no  in- 
flammation. If  this  appearance  should  be  accompanied  by  in- 
flammation, we  would  know  that  there  was  complication  and 
that  both  effects,  that  is,  auto-intoxication  and  clogging  were 
present.  Such  patients  always  confess  to  a  sweet  tooth  and 
nearly  always  have  bad  teeth.  Of  course,  correcting  the  errors 
of  refraction  in  such  a  case  could  not  begin  to  assist  Nature 
enough  to  effect  a  cure.  The  oculist  and  optician  do  not  know 
this,  and  the  case  is  not  only  a  failure  in  the  respect  of  getting 
eye  beneflts,  but  it  goes  on  to  its  death  through  their  ignorance 
by  getting  beyond  the  limit-angle  before  seeking  other  assist- 
ance. The  ophthalmologist  (the  real  one,  not  the  one  who 
merely  calls  himself  such)  knows  what  this  means  and  in  addi- 
tion to  prescribing  lenses  he  regulates  the  diet  quantitatively 
and  to  some  extent  qualitatively,  but  the  neurologist  goes  clear 
down  the  line  in  every  detail. 

So-called  "retinitis  syphilitica"  is  notable  for  the  absence 
of  the  "itis."  Retinitis  syphilitica  presents  peculiar  fantastic 
appearance,  sometimes  like  fern  leaves,  at  others  like  little 
black  lakes  connected  by  canals.  It  begins  well  forward  near 
the  edge  of  the  ciliary  body,  out  of  possible  view  by  the  indi- 
rect examination,  and  works  its  way  backward  toward  the 
macula,  until  a  patient  looking  at  the  line  "C.  L.  D."  on  the 
test  card,  for  example,  can  only  see  the  "  L. "  or  one  letter  at  a 
time,  so  small  is  the  field  of  vision;  it  is  quite  frequently 
found  in  children,  and  is  of  course  congenital;  it  also  occurs 
in  those  who  have  had  syphilis,  and  if  it  takes  this  form  of 
sensation  interference,  it  rarely  if  ever  develops  motor  trouble, 


ABOUT   ALLEGED   EYE  DISEASES.  J5J 

while  if  it  attacks  the  motor  nerves,  producing-  ataxia,  it 
rarely,  if  ever,  develops  the  other  form.  The  probable  reason 
is,  that  the  chemical  reactions  are  of  such  a  nature  that  the 
line  of  least  resistance  in  one  case  is  sensory  and  in  the  other 
is  motor ;  or,  in  other  words,  in  one  instance  the  chemical  reac- 
tions are  not  sufficient  to  produce  motor  energy  and  in  the 
other  are  insufficient  for  sensory  energy.  All  we  can  do  in 
either  case  is  to  get  the  best  possible  chemical  situation;  so 
that  nature  may  arrest  the  progress  in  either  case. 

Sometimes  there  will  be  intense  injection  of  a  vessel,  so 
that  it  appears  puffed  almost  to  the  bursting  point ;  this  occurs 
as  a  product  of  a  condition  of  the  blood  in  which  the  formation 
of  emboli  or  thrombi  (plugs)  occurs;  the  current  of  the  arter- 
ies being  from  the  disk  the  embolus  is  always  at  the  farther 
end  of  the  swollen  place ;  the  current  of  the  veins  being  toward 
the  disk  the  thrombus  is  always  at  the  nearer  end  of  the 
swelling-;  manipulation  of  the  eye  ball,  therefore,  might  dis- 
place the  plug  in  the  vein  because  it  would  push  it  toward  the 
larger  opening;  but  it  would  only  tighten  the  plug  in  an 
artery;  in  either  case  there  is  danger  of  rupturing  the  ves- 
sels, therefore  the  best  way  is  to  attack  it  chemically,  requiring 
absolute  rest  and  using  abundance  of  salt  in  the  diet ;  the  lat- 
ter does  not  thin  the  blood,  as  is  popularly  imagined,  it  merely 
reduces  the  lymph  or  plasma  or  liquor  sanguinis  to  a  normal 
liquid  state,  thus  the  plugs  are  dissolved.  If  hemorrhage  has 
already  occurred,  the  extravasated  blood  will  be  seen  as  a  sort 
of  a  splash,  almost  at  right  angles  to  the  vessel,  and  from  five 
to  fifteen  or  twenty  times  as  wide ;  this  is  provided  the  hyaloid 
membrane  is  intact,  otherwise  the  vitreous  will  be  discolored 
and  little  or  nothing  can  be  seen  with  the  ophthalmoscope;  if 
the  hemorrhage  occurred  so  long  before  we  see  it  that  reab- 
sorption  has  taken  place  there  will  be  white  streaks  alongside 
the  vessel  produced  by  the  emptying  of  capillaries  which  col- 
lapsed and  never  refilled. 

By  examining  one  another's  eyes  in  class  and  by  exam- 
ining not  only  patients,  but  persons  supposed  to  be  in  perfect 


J  52  OPTICAL   TRUTHS. 

health,  blondes  and  brunettes,  young,  middle  aged  and  old, 
males  and  females,  we  learn  the  average  size  of  the  vessels ;  the 
normal  color,  and  are  thus  able  to  recognize  instantly  any 
deficiency  in  the  quantity  or  quality  of  the  arterial  system, 
which  represents  the  entire  body  and  we  know  when  the  veins 
are  too  dark,  indicating  a  lazy  liver.  We  recognize  anaemia  by 
the  arteries  and  the  toxic  condition,  commonly  known  as  ma- 
laria, by  the  veins;  by  incidentally  catching  a  whiff  of  the 
breath  of  the  patient,  we  can  distinguish  catarrh  or  acute  liver 
disorder,  or  a  simple  temporary  stomach  disorder;  catarrh  has 
a  dirty  black  odor,  something  like  a  morgue,  the  bad  liver  has  a 
dark  brown  odor,  while  simple  indigestion  is  either  a  mild 
gray  or  a  sloppy  yellow  odor.  It  will  also  be  found  that  in 
healthy  children  the  arteries  and  veins  are  so  nearly  alike  we 
distinguish  them  only  by  the  veins  being  larger,  therefore  any 
child  presenting  the  appearance  of  an  older  person,  is  not  in 
perfect  order,  and  the  older  person  presenting  the  appearance 
of  a  child  is  in  prime  condition.  As  we  grow  quite  old,  long 
past  the  age  of  maturity,  the  amount  of  carbon  dioxide  in- 
creases even  in  health,  making  the  veins  quite  dark,  while  the 
arteries  are  somewhat  paler  than  middle  age.  For  corrobor- 
ation, let  an  old  person  sleep  in  a  close  room,  and  two  healthy 
children  in  another  of  the  same  size,  then  compare  the  two 
rooms  next  morning. 

In  myopes  the  vessels  usually  appear  large  for  two  rea- 
sons :  First,  they  usually  are  larger ;  second,  we  observe  them 
through  a  more  powerful  dioptric  system.  In  hyperopes  they 
often  appear  smaller,  because,  first,  they  often  are;  second, 
because  we  are  looking  through  a  weaker  dioptric  system. 
While  we  may  observe  the  general  systemic  system  through  one 
eye,  we  should  examine  both  eyes  to  observe  local  conditions. 
If  one  eye  has  normal  vessels  and  the  other  has  very  small  ones, 
it  indicates  vision  in  that  eye  will  not  be  good,  and  there  will 
be  little  hope  of  improving  it.  There  will  also  be  noted  a 
decided  difference  in  the  size  of  the  disk.  Sometimes  we  find 
both  eyes  much  undeveloped,  and  we  rarely  get  normal  vision. 


ABOUT   ALLEGED  EYE  DISEASES.  153 

If  there  is  a  vast  difference  in  the  two  eyes,  yet  the  appar- 
ently undeveloped  one  is  highly  astigmatic,  there  is  more  hope 
of  development,  and  if  the  internal  appearance  is  about  equal, 
the  chances  are  good  for  development.  This  is,  of  course,  not 
all  due  to  the  glasses,  but  the  systematic  treatment  would  be 
fruitless  without  them. 

One  of  our  means  of  noting  the  progress  of  a  case,  is  by 
observing  the  blood,  and  we  hold  that  no  doctor,  of  whatever 
school,  is  competent  to  practice  justly  to  himself  or  patient, 
without  understanding  practically  the  ophthalmoscope,  how  to 
fit  glasses,  manual  therapy,  dietetics  and  the  power  of  mind 
over  matter. 

If  there  are  wart-like  dilations  of  the  vessel  they  indicate 
a  dangerous  condition  of  the  walls  and  a  lack  of  the  elements 
necessary  for  strength  in  them.  These  dilations  are  called 
aneurisms  and  they  are  doubtless  present  elsewhere  in  the  body 
with  great  liability  of  fatal  termination  from  interstitial  hem- 
orrhages. We  pile  in  the  plus  foods  and  keep  the  patient  ex- 
tra quiet,  reduce  flesh  and  increase  the  strength. 

If  everything  appears  normal,  but  the  vision  is  bad  and 
cannot  be  fixed,  there  may  be  atrophy  of  the  main  trunk  of  the 
nerve,  or  of  the  fine  branches  forming  the  macula.  We  decide 
between  atrophy  and  paralysis  by  the  patient's  story,. if  vision 
was  lost  suddenly  it  could  not  be  atrophy,  if  it  went  slowly  it 
could  not  be  anything  else,  provided  the  media  are  clear. 

Of  course  opacities  of  the  cornea,  aqueous,  crystalline  or 
vitreous  impair  vision,  and  if  in  the  crystalline  humor  the  term 
"cataract"  is  applied,  if  in  the  vitreous  or  aqueous,  it  is  called 
a  "nebula,"  meaning  cloud,  or  a  "macula,"  meaning  spot. 
These  terms  are  also  applied  to  some  corneal  opacities,  al- 
though they  are  more  frequently  termed  cicatrixes,  meaning 
scars,  because  they  usually  come  from  ulcers.  Sometimes 
there  are  blind  spots  at  the  retina,  which  at  times  interfere 
with  vision  to  some  extent;  for  instance,  a  person  looking  at 
the  test  card  would  see  all  the  letters  except  at  the  lower  left, 
upper  right  or  some  small  part  of  the  field.     This  is  called  a 


J54  OPTICAL  TRUTHS. 

'scotoma."  Or,  it  may  cover  one-half  of  the  field;  for  in- 
stance, if  a  patient  with  his  right  eye  would  see  the  left  half  of 
the  card,  it  would  be  called  "hemiopsia"  or  "hemianopsia." 

Myopia  is  an  overdevelopment  of  the  globe,  or  increased 
volume  of  vitreous,  so  that  the  principal  focus  is  in  front  of 
the  retina;  in  case  of  general  overdevelopment  there  may  be 
very  good  vision  with  correct  glasses,  but  if  the  eyes  appear 
to  be  overdeveloped,  while  the  rest  of  the  person  is  under- 
sized, we  are  suspicious  it  belongs  to  the  class  of  increasing 
volume  of  vitreous,  hence  naturally  progressive  and  malig- 
nant; therefore,  unless  we  make  such  systemic  changes  as  will 
stop  the  tendency,  there  will  be  posterior  staphyloma,  which 
means  a  bulging  of  the  posterior  pole,  from  intraocular  pres- 
sure, with  the  result  that  the  retina  will  be  torn  and  the  macula 
destroyed.  If  we  get  a  case  that  has  already  reached  a  de- 
cidedly progressive  condition,  the  large  vessels,  which  meet  in 
the  center  of  the  disk  normally,  will  make  a  right  angle  turn 
toward  the  nose  in  the  field  of  the  disk,  and  at  the  temporal 
edge  of  the  disk  there  will  be  a  well-defined  white  meniscus. 
This  is  called  the  myopic  crescent.  If  the  staphyloma  has 
reached  a  bad  stage,  there  will  be  a  great  patch  at  the  posterior 
pole,  possibly  interspersed  with  fragments  of  pigment  and 
little  blood  clots.  .Vision  will  be  very  bad  and  little  or  noth- 
ing can  be  done  for  it.  There  is  another  form  of  myopia  in 
which  the  eyes  are  very  small,  but  shaped  like  an  acorn  or 
pecan,  hence  the  myopia.  These  will  be  found  in  persons  who 
are  congenitally  deficient  in  every  other  respect,  and  the  ma- 
jority of  cases  thus  far  found,  have  been  the  children  of  di- 
minutive parents,  or  of  diseased  ones,  and  it  is  not  unusual  for 
females  of  this  class  to  have  dysmenorrhea,  vicarious  menstru- 
ation, violent  tempers  and  end  in  insanity. 

There  are  physiological  appearances,  which  sometimes 
disturb  the  beginner,  but  which  need  not  when  the  character- 
istics are  known.  There  may  be  great  patches  of  pigment  with 
smooth  but  irregular  edges  or  the  patches  may  be  as  white  as 
the  whitest  porcelain;  the  large  vessels  will  be  seen  to  pass 


ABOUT  ALLEGED  EYE  DISEASES.  J55 

under  one  edge,  and  out  at  the  other  without  any  inflammation 
or  other  pathological  indications.  Around  the  edge  of  the  disk 
we  frequently  find  pigment,  because  the  layers  are  connected 
at  that  point  and  at  the  sclero-corneal  margin,  being  in  simple 
contact  the  rest  of  the  way.  Then  there  may  be  other  ex- 
hibits, such  as  a  speckled  field,  which  has  been  called  retinitis 
punctata  albecens,  in  its  pathologic  form,  but  when  found  and 
vision  is  unimpaired,  or  can  be  made  perfect  with  lenses,  we 
know  it  is  a  physiological  freak. 

The  so-called  pulsating  veins  will  always  be  found  inter- 
locked with  an  artery,  so  that  the  latter 's  impulse  is  felt  by  the 
vein  at  the  crossing  point  and  the  congestion  thus  caused  would 
lead  to  the  belief  a  thrombus  was  present,  except  for  the  pulsa- 
tion.   Nothing  can  be  done  for  it,  and  nothing  is  needed. 

Pathologic  conditions  sometimes  leave  apparent  physiolog- 
ical ones,  or  the  latter  may  have  been  so  situated  as  to  impair 
vision  or  rather  prevent  its  development  from  childhood.  In 
such  cases  we  watch  it  long  enough  to  see  that  it  is  not 
progressive. 

In  high  degrees  of  myopia,  or  in  very  old  people  with  small 
pupils,  it'^is  sometimes  difficult  to  see  the  fundus,  because,  in 
the  first  place,  of  the  increased  corneal  curvature,  reducing  the 
limit  angle  of  approach,  and,  in  the  second  place,  the  smallness 
of  the  pupil.  Nobody  ever  got  too  old  to  have  their  pupils 
dilated  with  atropine.  Use  No.  336  homatropine  disks,  1-500 
gr.  each.  For  younger  people  use  No.  338 ;  or  can  be  used  on 
anybody. 

The  +  and  —  lenses  may  be  turned  in  for  high  degrees  of 
error,  but  the  first  thing  is  to  get  the  right  angle  of  approach, 
which  is  from  15  to  20  degrees  from  the  axis  of  the  eye  ob- 
served. 

A  pterygium  is  designated  technically  as  a  vascular  thick- 
ening of  the  ocular  conjunctiva.  The  conjunctiva  is  the  mem- 
brane that  lines  the  lids  and  covers  the  anterior  portion  of  the 
globe,  including  the  cornea ;  the  part  that  lines  the  lids  is  the 
palpebral  portion  and  that  which  covers  the  globe  is  the  ocular 


156 


OPTICAL   TRUTHS. 


Fie:.  76 

portion.  These  growths  are  the  products  of  irritation  of  the 
nervous  system,  produced  from  within  by  the  strain  of  at- 
tempting to  overcome  hyperopia,  and  from  without  by  the 
presence  of  fine  dust,  which  accumulates  in  the  nasal  canthus 
because  the  flow  of  tears  carries  it  there.  The  irritation  of  the 
nerves  increases  the  heat  in  that  vicinity  and  nature  proceeds 
to  build  more  blood  vessels  and  to  enlarge  the  ones  already 
there  in  order  to  keep  the  membrane  cool.  They  are  easily  ar- 
rested, if  taken  before  they  get  too  much  of  a  start,  by  cor- 
recting the  hyperopia,  if  any  exists,  and  by  using  strong  salt 
water  with  a  delicate  atomizer,  twice  a  day  for  several  days. 
Sometimes  they  disappear  entirely.  If  they  are  neglected  too 
long,  and  grow  up  over  the  cornea  they  impair  vision  perma- 
nently. Some  malignant  cases  of  long  standing  have  to  be  dis- 
sected away.  Fig.  76  shows  one  grown  to  the  edge  of  the 
cornea. 

Cataracts  are  opacities  of  the  crystalline  lens.  They  are 
of  several  forms,  from  that  of  a  spider- v/eb  to  a  solid  mass. 
The  latter  are  seen  easily  and  appear  under  an  oblique  illumin- 
ation as  a  milky  spot  just  behind  the  pupil.  Congenital  cat- 
aracts are  those  which  exist  at  birth  and  are  usually  as  white 
as  ivory;  traumatic  cataracts  are  those  caused  by  blows  and 
they  may  mature  in  a  night;  senile  cataracts  are  those  which 


ABOUT   ALLEGED   EYE  DISEASES. 


J57 


come  in  the  eyes  of  old  people  from  the  systemic  changes  inci- 
dent to  their  age.  Fig.  77  shows  a  cataract  in  the  center  of  the 
pupil. 

Formerly  the  only  remedy  was  operation,  and  that  often 
failed  to  restore  sight  because  the  retinal  connections  with  the 
brain  had  become  atrophied  from  non-use.  It  is  not  advisable 
to  operate  as  long  as  the  other  eye  is  usable. 

Some  success  has  been  had  from  the  use  of  succus  cineraria 
maritima,  some  from  oil  of  thuja  oxidentalis,  and  some  from 
a  saturated  solution  of  common  salt.  It  requires  about  three 
months  to  make  the  latter.  All  of  them  are  used  in  the  same 
manner,  that  is,  a  drop  on  the  cornea,  just  above  the  pupil, 
three  times  a  day.  They  enjoy  about  the  same  per  cent  of 
success  as  do  other  chemicals,  medicines,  etc.,  and  no  one 
knows  why  they  work  when  they  do  or  why  they  fail  when 
they  do  that. 


m 


CLINICAL  HINTS. 

Have  a  private  office  and  when  admitting  friends  and 
relatives  of  patients  have  the  seat  they  are  to  occupy  screwed 
to  the  floor.  Never  have  more  than  one  extra  person  in  at  a 
time  and  have  a  strict  understanding  at  the  beginning  that 
they  are  not  to  speak  unless  spoken  to,  explaining  that  the 
nervous  system  is  a  delicate  thing  which  is  liable  to  go  -[-  or  — 
from  causes  produced  by  the  operator,  to  say  nothing  of  outside 
interference. 

It  pays  to  have  a  large  and  cheerful  reception  room  with 
magazines  and  papers  for  the  entertainment  of  guests  and  pa- 
tients, and  a  neat  reception  girl  to  receive  them. 

Spend  less  time  in  your  own  reception  room  than  any- 
where else.  If  not  busy  with  patients  your  work  room  is  your 
place  during  work  hours. 

Free  consultation  is  proper,  but  limit  it  to  fifteen  minutes, 
during  which  you  can  make  an  estimate  of  the  case,  state  the 
amount  of  your  fee,  and  how  it  is  to  be  paid;  require  a  por- 
tion of  it  paid  at  once  to  bind  the  appointment  for  the  exam- 
ination, stating  to  the  patient  that  you  have  been  compelled 
to  make  this  arrangement  to  apply  to  all  equally  for  two  rea- 
sons :  First,  to  insure  promptness  in  keeping  the  appointment ; 
second,  because  some  people  will  make  an  appointment  when 
they  know  they  cannot  pay  the  fee  and  do  not  want  to,  hence 
have  no  intention  of  keeping  it. 

Have  a  distinct  understanding  that  when  you  take  a  case 
and  have  specified  the  time  they  are  to  be  in  your  care,  the 
patient  having  agreed,  you  will  tolerate  no  interference  or 
suggestions  from  relatives,  alleged  friends  and  others  com- 
monly known  as  "buttinskies." 

When  a  patient  attempts  to  argue  or  to  persuade  you  to 
change  your  methods  to  suit  his  convenience  after  you  have 
made  an  analysis  and  found  what  is  necessary,  show  the  risk 
that  both  of  you  assume  by  it,  and  explain  that  these  calcula- 


160  OPTICAL   TRUTHS. 

lions  are  not  the  fads  of  a  school  of  medicine,  but  are  direct 
from  infinity.  If  any  fail  to  see  the  point,  dismiss  them ;  they 
are  breeders  of  trouble. 

The  average  heart-beats,  forward  and  back,  in  the  adult 
are  about  80  per  minute;  in  children  they  are  somewhat  more 
frequent,  and  in  the  aged  are  slower.  Therefore,  when  we  find 
a  grown  person's  heart  running  rapidly  it  indicates  irritation 
of  the  nerve  supply,  and  if  we  find  that  of  a  child  running 
slowly  it  suggests  weakness  or  an  unusual  slowness  for  physi- 
ological reasons ;  such  children  are  usually  termed  phlegmatic, 
opposed  to  nervous.  When  the  heart  is  unusually  slow  or 
rapid,  keep  the  ear  to  the  chest  for  several  minutes  to  see  that 
the  rhythm  is  perfect,  which  is  the  main  thing.  The  very  rapid 
hearts  often  drop  a  beat  in  five  or  ten  and  usually  begin  strong 
and  taper  down  until  they  drop  a  beat ;  those  are  positively  not 
mitral  valve  troubles,  nor  do  they  involve  any  of  the  valves 
of  the  heart  as  causative  factors.  The  whole  trouble  is  in  the 
weak  nerve  supply,  as  may  be  readily  proved  by  having  the 
patient  lie  flat  on  a  table  or  the  floor  for  ten  minutes.  The 
cause  of  the  nerve  weakness  may  be  in  one  of  many  depart- 
ments. 

After  taking  the  data  upon  which  your  prescription  is  to 
be  based,  unless  the  case  is  a  very  simple  one,  take  a  day  to 
figure  it  out,  in  the  meantime  requiring  absolute  rest,  and  it 
is  not  a  confession  of  incompetence  to  repeat  some  tests  on  a 
second  visit.  It  is  easy  to  explain  to  the  patient  by  showing 
the  sheet  upon  which  the  calculations  were  made  that  this  is 
part  of  our  method  of  procedure  which  enables  us  to  be  sure 
we  are  right. 

The  matter  of  diet  should  be  figured  out  by  taking  the 
principal  things  they  have  been  eating,  casting  up  the  points 
of  carbon,  nitrates,  phosphates  and  water  and  preparing  the 
diet  so  that  the  figures  reverse,  to  whatever  extent  we  deem 
necessary;  that  is,  if  what  they  have  been  eating  runs  four 
points  carbon  to  one  or  two  points  nitrates  and  phosphates 
combined,  we  make  the  change  at  first  so  that  there  will  be  two 


CLINICAL  HINTS.  J6J 

points  of  nitrates  and  phosphates  to  one  of  carbon,  explaining 
to  the  patient  that  from  time  to  time  the  proportion  of  carbon 
should  increase,  but  never  be  allowed  to  get  as  high  as  it  was. 
See  book  "Neurology  and  Metaphysics." 

Children  and  old  people  require  more  delicate  handling 
mentally  and  physically  than  those  between  20  and  50,  be- 
cause the  children  are  not  yet  matured  and  old  folks  are  on 
the  decline.  Of  course  there  is  a  difference  in  individual 
cases,  even  in  those  classes. 

After  the  age  of  fifty  if  everyone  would  cut  out  starchy 
foods,  sweets,  such  as  pastry  and  all  breakfast  foods,  subsist- 
ing largely  on  nuts  and  vegetables  in  summer,  with  occasion- 
ally smoked  meats,  fish,  and  with  a  moderate  amount  of  other 
meat  in  winter,  they  would  come  as  near  having  the  elixir  of 
life  as  has  yet  been  discovered. 

Never  forget  to  wash  the  hands  with  soap  and  water, 
rinse  them  and  clean  the  finger  nails  before  beginning  work 
on  a  patient.  The  odor  from  sweaty  hands  is  offensive.  After 
a  patient  has  left  the  operating  room  open  a  window  and  spray 
a  little  perfumed  water  about. 

In  prescribing  temporary  lenses  for  neurasthenics  in  whom 
fogging  causes  nausea  remember  they  are  mentally  as  well  as 
physically  weak,  and  reduce  the  fog  to  the  comfort  point,  but 
keep  it  as  strong  as  you  can.  Fog  all  others  20/80,  or  even 
more,  because  they  are  not  nearly  as  liable  to  look  over  the 
glasses  as  if  you  gave  them  20/30  vision,  and  their  distant 
vision  will  be  almost  as  good,  while  it  is  still  a  constant  re- 
minder of  the  doctor's  orders. 

Beware  of  prescribing  cylinders  when  they  are  —  .50  or 

—  .75  or  less.  The  way  to  get  around  it  is,  after  proving  say 
a  —  .75  ax.  180,  slip  it  off,  hold  it  in  one  hand  and  have  a  — 
.25  sphere  in  the  other,  the  patient  looking  at  the  test  card; 
hold  the  cylinder  in  front  first,  then  take  it  away  and  try  the 
sphere;  if  vision  is  not  so  good,  compare  the  cylinder  with  a 

—  .50  sphere,  if  vision  is  best  with  the  cylinder,  leave  it ;  if  best 
with  the  sphere,  cut  out  the  cylinder  and  reduce  the  +  sphere 


162  OPTICAL  TRUTHS. 

accordingly.  If  there  is  no  -f  sphere  in  the  combination,  the 
rule  will  work  just  as  well  in  the  matter  of  substituting  the 
sphere  for  the  cylinder.  In  other  words,  theoretically,  if  a 
cylinder  is  correct  it  ought  to  give  as  good  or  better  vision 
than  a  —  sphere  of  the  same  strength,  and  the  fact  that  prac- 
tically in  the  amounts  below  one  diopter  it  rarely  gives  better 
vision  than  a  sphere  .25  or  .50  weaker  is  ample  proof  of  the 
doubtfulness  of  weak  cylindrical  corrections.  The  fact  that 
such  patients  see  a  difference  in  the  radiating  lines  of  the 
astigmatic  chart  without  the  cylinder  has  no  influence,  unless 
the  patient  is  going  to  do  such  work  as  would  involve  such 
lines,  and  if  he  has  been  doing  that  work  his  vision  will  be  so 
sensitive  that  he  will  never  let  us  substitute  the  sphere  in  the 
first  place. 

Remember  that  presbyopia  should  not  begin  in  emme- 
tropes  until  between  forty  and  fifty,  and  in  hyperopes  not 
until  between  forty-five  and  fifty-five,  hence  when  we  find 
one  under  the  minimum  age  who  seems  to  require  reading 
glasses  it  is  evidence  of  a  nervous  deficiency  which  should  be 
rested,  dieted,  etc.  Particularly  with  reference  to  hyperopes 
under  forty-five  who  have  say  1.00  D.  or  more  error,  but  who 
have  not  worn  glasses,  and  insist  they  only  want  them  for 
reading,  we  explain  that  while  they  might  be  reasonably  com- 
fortable with  such  glasses  for  a  while  they  are  breeding  trouble 
as  certain  as  death  or  taxes,  and  in  nine  cases  out  of  ten  it 
begins  at  once,  because  the  nerve  supply  being  exhausted 
when  the  reading  glasses  are  put  on  and  the  incoordination 
remaining  between  accommodation  and  convergence,  comfort 
is  almost  an  impossibility.  Sometimes  we  make  a  concession 
to  such  people,  which  is  to  give  them  the  glasses  they  should 
wear  constantly,  which  of  course  will  be  some  help  for  reading, 
and  after  explaining  the  above  described  situation,  tell  them 
when  they  find  these  are  not  comfortable  or  are  irritable  that 
it  is  a  message  from  Nature  telling  them  they  must  wear  them 
all  the  time. 

Never  make  bifocals  for  myopes,  except  possibly  in  a  rare 


CLINICAL  HINTS.  J63 

case  when  the  distant  glass  is  —  .50  or  —  .75,  because  in  the 
higher  amounts  the  prismatic  effect  is  unpleasant  on  account 
of  chromatic  aberration.  In  making  bifocals  for  others  the 
scale  for  cements  should  be  13  mm.  high,  15  mm.  long,  1  mm. 
up  from  the  lower  edge  of  the  lens ;  they  may  be  set  in  a  little, 
say  2  mm.  toward  the  nose  to  suit  the  convergence  while  using 
them. 

The  pupil  distance  in  glasses  for  hyperopes  should  be  a 
trifle  narrow  than  otherwise,  because  they  are  going  to  use 
them  near  and  far,  while  for  myopes  they  may  be  made  full 
width. 

Hook  temples  for  glasses  should  be  made  long  enough  so 
that  the  tip  is  just  concealed  behind  the  lobe  of  the  ear.  Then 
there  is  no  irritation  from  the  pressure  of  the  temple  which  is 
sometimes  very  annoying  if  they  are  made  too  short. 

In  cases  where  the  eyes  differ  so  much  that  one  has  been 
used  to  the  exclusion  of  the  other,  or  when  there  are  oblique 
axes,  the  discomfort  produced  at  first  is  so  great  that  it  may 
even  cause  sea-sickness.  This  should  be  explained  previously 
so  that  the  patient  will  not  become  frightened,  and  we  should 
insist  upon  their  sticking  to  them,  when  the  trouble  will  be 
over  in  a  few  days,  while  otherwise  it  would  last  for  weeks. 
The  oculists  who  have  perpetrated  books  call  this  the  point  of 
toleration  and  advise  against  prescribing  for  such.  Toleration 
of  drugs  is  one  thing  and  of  mechanical  appliances  another. 

In  working  on  cross-eyes  when  the  patient  complains  of 
seeing  double  we  know  they  are  coming. 

Sometimes  in  simple  cases  of  hjrperopia  the  patient  returns 
in  two  or  three  days  with  a  frightful  looking  case  of  conges- 
tion of  the  conjunctiva,  for  which  there  may  be  two  causer,  or 
a  combination  of  both;  first,  they  may  have  caught  cold  and 
congestion  centered  in  the  eyes  because  it  was  a  weak  spot  and 
offered  the  most  resistance  to  the  current,  or  the  circles  of 
diffusion  at  the  retina  caused  by  the  lens  and  accommodation, 
from  the  myopia  thus  created,  but  the  controlling  center  hav- 
ing been  accustomed  to  turning  on  the  power  for  circles  of 


164  OPTICAL  TRUTHS. 

diffusion  tackled  this  one  and  the  results  are  plain.  Reassure 
the  patient  by  making  a  drawing  showing  the  story;  have  him 
go  home  and  rest  a  day,  using  salt  water,  when  he  will  be 
all  right. 

In  prescribing  applications  for  the  eyes,  remember  that 
cold  contracts  and  heat  relaxes,   therefore,   hot  water  com- 
presses are  to  be  applied  in  cases  of  tonic  spasm  with  pain. 
It  would  do  no  harm  to  salt  it  except  that  salt  is  an  astringent, 
hence  would  have  a  tendency  to  counteract  the  action  of  the 
warmth,  especially  in  the  conjunctiva,  through  which  part  of 
the  excess  blood  from  the  ciliary  body  finds  its  way  to  the 
veins  of  the  face.     Sometimes  hot  water  does  not  accomplish 
the  desired  effect  in  a  reasonable  time,  say  an  hour,  then  we 
alternate  with  cold,  but  not  ice  water.     Another  case  in  which 
we  use  hot  water  is  when  there  is  suppuration,  the  lids  stick 
together  and  a  wax  forms  among  the  lashes;  hot  water  will 
dissolve  this  wax,  which  is  impervious  to  the  cold.     It  should 
be  used  with  a  soft  cloth,  and  five  minutes  to  each  eye  will 
make  it  perfectly  clean;  then  apply  cold  salt  water  compresses 
for  the  purpose  of  cooling  the  temperature  and  for  forcing 
the  blood  from  the  veins  by  contracting  the  nerves  both  from 
the  cold  and  astringent  effect  of  the  salt,  while  the  latter  also 
antisepticizes  the  membrane  and  takes  the  gum  out  of  the  lach- 
rymal fluid.     In  very  bad  cases  of  ulceration  of  the  ocular  con- 
junctiva, or  granulation  of  the  palpebral  portion,  they  should 
be  freely  sprayed  from  an  atomizer  containino    strong  salt 
water,  neither  hot  nor  cold,  about  four  times  a  day,  a  few 
good  shots,  one  squarely  against  the  eyeball,  one  under  the 
upper  lid  and  one  on  the  under  lid.     The  two  latter  may  be 
made  at  one  dash  and  should  be  directed  toward  the  nasal 
canthus;  then  following  this  the  patient  should  lie  down  and 
apply  the  cold  salt  water  for  a  half  hour.     One  of  the  treat- 
ments should  be  at  bedtime,   another  the  first  thing  in  the 
morning. 

In  epilepsy,  chorea  or  other  nervous  exhibits,  remember 
they  are  not  diseases,  and  the  fact  that  drugs  have  failed  in 


CLINICAL  HINTS.  J65 

curing  them  proves  that  they  must  be  from  mechanical  causes, 
as  that  is  the  only  classification  left.  It  is  true  that  under 
such  conditions  the  chemistry  of  the  stomach  will  be  imperfect, 
and  while  many  of  the  attacks  come  on  after  eating,  still  it  is 
more  mechanical  than  chemical  even  then,  because  they  always 
have  the  fits  in  such  cases  just  after  overloading  the  stomach, 
thus  proving  that  it  is  quantitative  rather  than  a  qualitative 
proposition.  Of  course  we  look  after  the  eyes  among  other 
things,  and  we  may  safely  devote  more  attention  to  mechanics 
even  though  as  a  matter  of  course  we  watch  the  quality  as  well 
as  quantity  of  food. 

The  use  of  prisms  as  a  treatment  for  cross-eyes  is  foolish,  . 
for  so-called  muscular  insufficiencies,  a  misdemeanor,  and  to 
use  them  to  prevent  double  vision  is  a  felony,  because  it  creates 
cross-eyes.  Eyes  may  cross  up  or  down,  in  or  out,  and  the  way 
a  prism  prevents  double  vision  is  by  practically  excluding  one 
eye  so  that  a  so-called  single  vision  is  with  the  other  alone  and 
is  not  binocular. 

Some  very  sensitive  people  occasionally  complain  of  seeing 
every  object  with  a  sort  of  spot  in  the  center,  particularly 
small  objects  like  letters,  and  sometimes  they  explain  that 
there  appear  to  be  two  objects,  the  ghost  on  top  of  the  real. 
A  young  lawyer  of  Chicago  came  complaining  of  this  symptom 
and  said  that  a  prominent  oculist  had  made  an  examination 
and  told  him  that  he  had  had  a  hemorrhage  in  his  left  eye 
which  left  a  spot  of  extravasated  blood  which  caused  the 
symptom.  Inasmuch  as  the  size  of  the  retinal  fieild  occupied 
by  the  image  of  a  small  letter  at  twenty  feet  would  be  very 
small  and  the  spot  of  blood  would  have  to  be  smaller,  some- 
thing the  size  of  a  pin  point,  it  struck  me  that  the  doctor  was 
either  a  marvelous  man  or  liar,  and  when  the  patient  told  me 
that  if  he  covered  one  eye,  it  made  no  difference  which,  the 
spot  disappeared,  I  became  firm  in  the  latter  conclusion.  Then 
he  demanded  an  explanation  from  me.  He  was  the  most 
highly  strung  nervously  of  all  the  patients  I  have  ever  had  and 
I  reasoned  that  it  must  be  a  case  of  anisometropia,  and  as 


J66  OPTICAL   TRUTHS. 

vision  was  so  keen  with  either  I  suggested  that  possibly  he  had 
.75  hyperopia  in  one  eye  and  1.25  hyperopia  in  the  other  or  1.00 
in  one  eye  and  1.50  in  the  other  and  when  using  both  eyes 
together,  accommodating  the  same  amount  in  each,  it  left  one 
under-corrected  .50  or  the  other  over-corrected  .50,  which 
would  be  just  sufficient  to  make  the  ghost  appear.  After  ex- 
plaining this  proposition  to  a  class  I  used  him  as  a  clinic  and 
found  .75  hyperopia  in  one  eye  and  1.25  in  the  other  and  with 
these  glasses  on  the  ghost  disappeared. 

The  last  paragraph  suggests  another  case  which  is  not 
often  found.  It  is  possible  sometimes  to  give  a  patient  pretty 
good  vision  for  distance  with  correction,  but  when  it  comes 
to  the  reading  point  no  glasses  will  help  and  if  the  accommo- 
dation is  active  in  a  young  person  he  cannot  see  to  read.  This 
is  because  a  very  small  field  in  the  center  of  the  macula  is 
healthy  and  sufficiently  large  to  receive  the  small  image  of 
distant  objects,  but  immediately  outside  of  that  there  is  a  dead 
space,  hence  the  larger  images  of  near  objects  are  not  trans- 
mitted to  the  brain.  Again  a  case  may  be  found  where  dis- 
tant vision  is  bad  and  cannot  be  improved,  yet  the  patient 
can  see  reasonably  well  to  read  even  without  glasses.  In  this 
instance  the  situation  is  reversed;  it  is  a  central  atrophy  with 
a  healthy  periphery. 

When  a  patient,  or  other  person,  happens  to  faint  in  your 
presence  or  have  any  kind  of  a  falling  fit,  be  careful  to  keep 
the  body  horizontal,  if  any  change  put  the  head  the  lowest, 
and  apply  cold  water,  either  sprinkle,  dash  or  use  wet  cloths. 
A  bottle  of  strong  pleasant  perfume  is  better  than  camphor, 
ammonia  or  any  other  drugs.  A  sip  of  clear  water  is  better 
than  liquor  and  not  half  so  liable  to  strangle.  Manipulate 
the  arms  and  legs  a  little,  but  be  careful  not  to  worry  the 
patient.  As  soon  as  consciousness  is  restored  a  little  pinch  of 
salt  or  a  swallow  of  lemonade  will  settle  the  stomach.  In  the 
convulsions  of  fits  do  not  undertake  to  hold  the  patient  rigid, 
but  just  keep  him  from  hurting  himself. 

By  way  of  illustrating  the  deviltry  of  prisms  we  have 


CLINICAL  HINTS.  167 

the  following  showing  the  relative  proportion   of  the  total 
strain  to  the  original  impulse  in  an  emmetrope  whose  conver- 
gence was  irritated  to  the  amount  of  1.00  D.  with  a  4'  prism 
and  a  hyperope  of  1.00  D. 
Convergence  from  4°  base  out,     L.    .50 

R.    .50  1.00  original  impulse 
Automatic  accommodation,         L.  1.00 

R.  1.00   2.00    automatic   in- 
crease. 


3.00  total  damage. 
Increase  over  original  impulse,  200  per  cent. 
Effect  of  hyperopia: 
For  accommodation,  L.  1.00 

R.  1.00  2.00  original  impulse. 
Automatic  convergence,  L.    .50 

R.    .50  1.00  automatic  incr. 
Negative  pull,  6th  N.,  L.    .50 

R.    .50 1.00  voluntary  incr. 


4.00  total  damage. 

Increase  over  original  impulse,  100  per  cent. 

The  old-fogy  idea  that  small  pupils  mean  spasm  and  large 
pupils  mean  the  reverse  has  caused  the  death  of  many  per- 
sons from  drugs  administered  wrongly.  To  us  the  significance 
of  the  size  of  the  pupil  is  absolutely  nothing  unless  corrobo- 
rated in  other  directions.  A  small  pupil  may  appear  in  a  de- 
bilitated person  who  couldn't  raise  energy  enough  to  have  a 
spasm  if  he  were  paid  for  it,  and  a  large  pupil  is  very  often 
found  in  people  with  a  severe  tonic  spasm  because  the  nerve 
branches  operating  the  iris  were  put  out  of  action  by  the 
ciliary  disturbance. 

In  cases  of  very  high  degrees  of  hyperopia,  say  6.00  D.  to 
10.00  D.  we  sometimes  find  after  getting  on  all  -{-  we  can  that 
in  adding  for  reading  it  takes  considerable  more  increase  of 
power  than  the  reading  distance  calls  for.    For  example,  we 


J68  OPTICAL   TRUTHS. 

have  found  +  6.00  and  have  to  add  +  4.00  for  reading  at  13 
inches.  Our  physics  tells  us  this  is  wrong',  so  increase  the  -(- 
6.00  to  -p  7.00  and  find  the  patient  sees  as  well  at  a  distance  as 
with  the  -f  6.00,  which  proves  once  more  that  the  Infinite 
Creator  did  not  make  a  mistake. 

Polyuria  is  not  indication  of  kidney  trouble  in  more  than 
one-tenth  of  the  cases  it  exhibits.  It  is  most  frequent  in 
women  and  the  old  schools  claim  it  is  proof  that  they  have 
more  kidney  trouble,  when  as  a  matter  of  fact  they  are  notably 
free  from  it,  and  the  symptom  is  nearly  always  due  to  a  stric- 
ture of  the  muscular  structure  around  the  neck  of  the  bladder 
due  to  sympathy  with  the  accommodative  effort  caused  by 
hyperopia. 

Similar  conditions  in  men  usually  mean  the  involvement 
of  the  prostate  gland  and  irritation  of  the  urethra,  which  is 
about  eight  inches  long.  In  these  cases  while  hyperopia  is 
often  a  primary  factor,  sexual  excitement  intensifies  the 
trouble  and  may  cause  it  in  emmetropes.  The  after-effects 
are  incontinence,  emissions,  and  finally  impotence.  The  treat- 
ment for  prostatitis,  hydrocele,  varicocele,  urethritis,  gonor- 
rhoea, are  all  the  same,  a  -j-  diet,  correction  of  eye  errors,  rest, 
avoidance  of  liquor  and  tobacco,  sexual  excitement  and 
bougies.  A  fine-pointed  rubber  syringe  may  be  introduced 
one-half  or  three-fourths  of  an  inch  and  cool  salt  water  in- 
jected night  and  morning;  otherwise  let  it  alone. 

Pains  are  nearly  always  referred  to  a  point  comparatively 
remote  from  the  primary  cause;  thus  a  disordered  liver  will 
cause  a  headache,  and  the  pressure  of  a  shoe  on  a  corn  will 
irritate  the  entire  nervous  system.  But  sometimes  pain  is 
referred  to  the  seat  of  the  primary  cause  by  reflex  action,  as 
for  instance  in  hyperopia  the  effort  to  overcome  it  by  accom- 
modation produces  a  tonic  spasm  throughout  the  entire  system 
and  the  pain  in  the  eyeballs  is  from  the  secondary  irritation. 

In  questioning  patients,  do  it  deliberately,  and  form  the 
habit  of  consecutiveness ;  that  is,  begin  with  the  questions 
regarding  memory,  etc.,  headache,  eyeaches,  toothache,  nose, 


CLINICAL  HINTS.  J69 

throat  and  ear  affections,  and  so  on  down.  Never  ask  a  ques- 
tion without  getting  an  answer;  if  the  patient  refuses,  close 
the  conference.  If  you  ask  to  take  the  patient's  glasses  and  he 
folds  them  up  and  puts  them  in  his  pocket,  get  the  glasses, 
then  deliberately  lay  them  aside  without  looking  at  them  and 
go  on  with  your  work.     This  is  part  of  the  true  fogging  system. 

Quite  frequently  we  have  for  patients  young  girls  from 
the  age  of  puberty  to  about  twenty  years,  whose  general  ap- 
pearance is  healthy  but  who  complain  of  a  constant  tired  feel- 
ing, and  the  examination  (ophthalmoscope),  shows  a  very 
great  lack  of  red  arterial  blood,  while  the  venous  blood  may 
not  be  off  color;  the  general  field  of  the  retina  will  be  quite 
pale,  and  sometimes  the  larger  veins  may  be  extra  dark.  Such 
people  will  confess  fainting  spells  or  at  least  attacks  of  nausea 
and  faintness,  even  if  there  is  no  swoon.  They  usually  suffer 
from  dysmenorrhoea  and  often  menstruate  every  three  weeks. 
Occasionally  cases  of  the  latter  kind  are  found  in  people 
thirty-five  years  old,  but  such  usually  show  debility  in  their 
countenance. 

Boys  between  the  ages  of  twelve  and  fifteen  often  go 
through  peculiar  systemic  changes  similar  to  those  of  girls, 
and  not  being  able  to  find  relief  in  menstruation,  become  so 
debilitated  that  they  do  not  regain  normal  vigor  until  about 
twenty,  unless  they  fall  into  our  hands  and  go  through  a  reg- 
ular course. 

Children  who  are  growing  actually  need  more  food  than 
grown  people ;  first,  because  they  have  not  only  to  sustain,  but 
to  build,  the  body;  second,  digestion  with  them  is  more  vigor- 
ous unless  it  is  suspended  by  overloading,  and  it  is  more  dif- 
ficult to  overload  them  to  that  point  because  the  muscular 
coat  of  the  stomach  is  more  elastic.  If  proper  attention  be 
paid  to  the  quality  of  their  food  there  will  be  a  more  even 
distribution  and  a  greater  return  from  the  amount  taken  in  the 
building  up  of  the  nerve  and  muscle  supply,  for  the  growing 
child  needs  more  of  the  -f-  elements  than  it  does  of  the  fat 
making  ones,  and  with  these  supplied  he  will  soon  eat  regu- 


J  70  OPTICAL   TRUTHS. 

larly  and  not  suffer  the  all-gone  feeling  a  half  hour  or  so 
before  meals.  But  provide  for  such  emergencies ;  let  him  have 
an  apple  or  an  orange,  because  it  will  not  affect  his  appetite. 
See  ' '  Neurology  and  Metaphysics. ' ' 

As  to  instruments  for  making  eye  tests,  after  the  ophthal- 
moscope I  would  rather  have  a  dollar  stereoscope  than  all  the 
phorometers,  optometers,  etc.,  on  the  market.  It  is  made  upon 
a  physical  principle  with  prisms  base  in  that  proves  our  physi- 
logical  principles  with  reference  to  the  meter  angle  of  con- 
vergence caused  by  prisms  base  out  or  saved  by  prisms  base 
in,  and  in  case  of  tonic  spasm  exhibited  by  the  +  impulse  in 
the  static  test,  we  might  use  such  an  instrument  successfully 
sometimes  in  an  effort  to  break  down  the  spasm. 

Referring  to  the  eyes  and  their  exhibits  of  spasms,  we 
have  two  kinds,  clonic  and  tonic ;  while  the  first  is  intermittent 
and  the  second  constant,  the  latter  being  only  a  more  intense 
form  of  the  first,  it  may  be  understood  readily  that  either  may 
tend  toward  the  other  because  the  dividing  line  is  not  estab- 
lished like  a  pencil  mark.  For  example,  a  tonic  spasm  may 
relax  a  little  under  our  manipulation  and  thus  become  clonic 
while  another  case  with  clonic  spasm  may  suddenly  become 
tonic  while  we  work  on  it.  This  may  even  go  so  far  that  the 
static  test  will  show  a  -f  impulse  before  correction  and  a  —  im- 
pulse afterward,  or  the  reverse.  This  is  why  we  make  the  static 
test  twice.  Clonic  spasm  is  expected  in  all  cases  under  the 
presbyopic  age,  that  is,  under  about  forty-five  years  and  when 
we  do  not  find  it  at  least  moderately,  it  is  sufficient  proof  of 
general  weakness  to  require  the  patient  to  stop  work.  A  mod- 
erate amount  of  it  can  be  controlled  by  our  systematic  meth- 
ods, mental  and  physical,  and  immoderate  amounts  are  treated 
the  same  as  tonic  spasm  because  they  are  bordering  on  that 
extreme  condition.  Such  cases  should  also  be  required  to  rest 
unless  the  dynamic  test  before  and  after  correction  guaran- 
tees a  bountiful  nerve  supply. 

While  it  is  against  the  principles  of  ophthalmology  to 
worry  a  patient  by  long-continued  efforts  to  break  down  tonic 


CLINICAL  HINTS.  J  71 

or  clonic  spasms,  yet  it  is  sometimes  possible  to  accomplish 
it  quickly  by  moving  the  patient  closer  to  the  test  card,  say 
ten  or  fifteen  feet,  when,  everything  being  more  distinct,  his 
controlling  center  gets  a  better  grip  on  it  and  we  can  at  least 
measure  and  prove  whether  there  is  astigmatism;  then  after 
reducing  the  spheres  until  vision  is  what  it  should  be  at  the 
distance  the  patient  is  seated,  if  the  static  test  shows  a  4- 
impulse  we  increase  the  spheres  arbitrarily  according  to  the 
neurometer  instructions.  Sometimes  we  find  it  best  to  not 
unfog  the  patient  until  he  sees  quite  as  perfectly  as  he  should, 
and  in  such  cases  when  it  comes  to  adding  for  his  -^  impulse 
we  must  allow  about  .25  for  the  amount  already  on. 

Clonic  spasm  must  not  be  confused  with  neurasthenia, 
as  it  is  liable  to  be  on  account  of  one  exhibit,  that  of  seeing 
better  one  moment  than  another  with  the  same  lens;  in  the 
clonic  spasm  the  patient  may  change  a  line  or  two  or  even 
more,  but  what  he  sees  each  time  will  be  distinct,  while  in 
neurasthenia  vision  is  fairly  good  one  moment  and  the  whole 
card  fades  away  the  next,  while  a  sensation  of  nausea  or  f aint- 
ness  will  be  admitted;  also  the  neurasthenic  will  exhibit  this 
feature  without  glasses. 

If  the  static  test  shows  a  —  impulse  it  is  either  neuras- 
thenia or  a  clonic  spasm,  but  if  the  test  shows  a  +  impulse  we 
would  always  class  it  as  tonic  spasm  although  in  some  cases 
we  might  be  able  to  push  it  over  into  clonic  and  correct  the 
error. 

Clonic  spasm  signifies  an  exceeding  irritation  and  very 
likely  cyclitis,  which  requires  rest,  for  two  reasons:  First, 
the  possibility  of  local  damage  from  adhesion  of  iris  and  lens 
in  cases  where  the  pupil  is  small,  or  possibly  from  infection 
of  the  conjunctiva  or  retina;  second,  the  liability  of  causing 
cerebral  hemorrhage  from  interference  with  circulation  by  the 
general  spasm.  This  is  more  liable  to  occur  in  persons  who 
are  extraordinarily  stout  and  who  have  reached  the  stage 
where  they  are  highly  nervous,  because  the  walls  of  the  blood- 
vessels are  weaker,  hence  more  liable  to  rupture.    There  is 


J72  OPTICAL   TRUTHS. 

also  the  possibility  in  thin  people  of  cerebral  paralysis  and 
softening  of  the  brain,  or  paresis,  which  is  practically  the 
same  thing. 

Catching  a  spasm  at  work  is  one  thing  and  getting  control 
of  it  is  another.  As  we  know  the  symptoms  we  know  posi- 
tively when  we  have  controlled  it  and  we  also  know  positively 
when  we  have  not.  In  the  latter  instance  we  fog  the  eyes 
and  demand  rest  until  the  spasm  breaks,  or  if  we  allow  the 
patient  to  continue  at  work,  which  we  should  not  do,  we  get  a 
written  contract  that  he  assumes  the  responsibility. 

The  static  test  may  show  orthophoria  from  a  tonic  spasm 
in  the  6th  nerves  as  well  as  the  3d,  but  in  such  cases  we  would 
detect  it  by  the  pain  intraocularly,  or  the  test  may  register 
zero  from  a  reasonably  good  supply  of  nerve  force  yet  the 
case  may  develop  quite  a  clonic  spasm  during  the  refraction 
test.  Such  cases  are  as  a  rule  easily  handled,  although  they 
are  liable  to  deceive  us  into  unfogging  too  much,  unless  we 
watch  them  carefully. 

Don't  forget  that  myopes  are  very  liable  to  spasm  from 
the  accommodation  coming  automatically  with  extraordinary 
convergence,  even  though  they  show  zero  or  —  impulse  by 
the  static  test.  The  possibilities  of  spasm  in  myopes  of  high 
degree  are  so  great  that  if  the  patient  is  seated  ten  feet  from 
the  card  without  being  able  to  see  it,  and  we  could  get  10/15 
vision  with  strong  lenses,  we  would  stop  them  at  10/80  if  they 
had  never  worn  glasses,  or  even  if  they  had  but  were  suffering 
from  hyperopic  symptoms,  unless  the  general  test  combined 
showed  such  weakness  as  would  warrant  giving  as  much  as 
10/15  or  10/20,  and  even  that  must  be  supported  by  the  fact 
that  the  lenses  we  give  are  so  decidedly  weaker  than  the  ones 
they  have  been  wearing  that  it  is  a  clear  case.  It  is  nothing 
for  us  to  steal  a  2  D.  or  3  D.  from  the  —  corrections  of  the 
average  oculist  or  optician  and  still  leave  vision  as  good; 
therefore  if  we  find  a  case  where  we  cannot  steal  as  much  as 
a  diopter  and  still  preserve  good  vision  we  steal  more  and  let 
the  vision  go. 


CLINICAL  HINTS.  173 

In  low  degrees  of  myopia  that  have  been  fitted  by  other 
people,  knowing  their  failings,  we  sail  in  to  get  -f  on,  and  in 
these  cases,  which  are  decidedly  the  worst  of  all  we  have  to 
deal  with,  because  they  are  liable  to  have  a  tonic  spasm  yet 
dodge  all  tests,  we  waste  no  time  but  fog  to  20/80  or  20/120. 
An  interesting  thing  about  these  cases  is  that  while  vision  may 
be  as  bad  as  20/60  with  the  naked  eye  we  often  get  a  4-  2.00 
on  and  vision  be  as  good  as  20/120,  and  we  finally  get  as  much 
as  a  -|-  1.50  cylinder  or  -|-  1.00  sphere  +  1.00  cylinder,  where 
the  other  fellow  has  —  1.00  or  —  1.50  cylinder,  and  we  some- 
times get  simple  -[-  spheres,  -|-  1.50,  where  they  have  been 
wearing  —  1.00  cylinders. 

Having  adopted  the  eyes  as  the  gauges  of  the  body,  and  util- 
ized them  as  such,  objectively  and  subjectively,  the  first,  macro- 
scopically  and  ophthalmoscopically,  the  second,  dynamically 
and  statically,  we  know  that  as  a  rule  deep-set  eyes  or  bulging- 
eyes  with  a  low  nose  bridge,  vertical  wrinkles  in  the  forehead, 
etc.,  are  objective  symptoms  that  the  gauges  will  need  fixing. 
The  subjective  tests  are  equally  simple  when  understood,  and 
much  more  certain,  indeed  we  diagnose  objectively  and  ana- 
lyze subjectively.  Djmamic  tests  of  the  gauges  mean  different 
things  at  different  ages  and  under  different  circumstances. 
The  operator  must  be  very  familiar  with  these  facts  and  know 
why  the  facts  are.  For  example,  children  under  ten  years  of 
age  rarely  show  any  more  power  by  the  dynamic  test  than 
those  of  that  age,  for  two  reasons,  first:  the  eyes  do  not  de- 
velop full  growth  and  power  until  about  the  age  of  ten  years ; 
second,  a  ten-year-old  can  reach  the  limit  angle  of  convergence, 
which  is  2  3/4  inches,  and  the  younger  child  could  do  no  more, 
hence  we  begin  our  figures  with  that  age  and  14.00  D.  Be- 
tween ten  and  twenty  years  the  child  may  have  enough  ac- 
commodation and  convergent  power  above  normal  to  overcome 
its  hyperopia  and  come  to  the  normal  point,  but  when  we  put 
on  the  correcting  -\-  lenses  it  will  not  be  able  to  show  any 
greater  power  than  before,  because  it  has  reached  the  limit 
angle  of  convergence,  but  we  know  that  it  has  more  power 


174  OPTICAL   TRUTHS. 

than  it  shows  with  the  lenses  because  it  came  to  the  same  point 
or  nearer  without  them.  Example:  Suppose  a  child  shows 
12.00  D.  accommodation  by  coming  to  3 1/4  inches  without 
glasses,  but  by  a  test  we  find  hyperopia  of  2.00  D.,  we  know 
that  in  order  to  come  to  3  1/4  inches  without  glasses  it  must 
have  been  accommodating  14.00  D.  and  we  give  it  such  credit 
even  if  it  can  show  only  11.00  D.  with  glasses  on.  If  such  a 
case  shows  an  increase  of  accommodation  after  correction  we 
know  it  should  not  be  able  to  do  so  were  it  in  good  condition ; 
therefore,  it  becomes  a  symptom  of  weakness  in  that  child  to 
show  strength.  Above  the  age  of  twenty  years  up  to  about 
thirty-five  years,  the  near  point  recedes  beyond  the  limit  angle 
of  convergence  on  account  of  the  decrease  in  his  dynamic 
facilities.  We  make  the  test  before  correction,  then  expect 
him  to  show  an  increase  equal  to  the  amount  of  -[-  sphere  in 
the  correction.  If  he  fails  to  do  it,  watch  out  for  spasm,  and 
if  he  shows  more  increase  than  he  should  it  is  a  symptom  of 
weakness  which  prevented  him  from  showing  as  much  as  he 
ought  to  in  the  first  place.  After  the  age  of  thirty-five,  when 
his  near  point  is  still  farther  away  and  his  dynamics  naturally 
weaker,  we  expect  him  to  show  an  increase  at  the  second  dy- 
namic test  two  or  three  times  as  great  as  the  -!-  sphere  in  the 
correction,  until  between  forty-five  and  fifty,  when  presbyopia 
begins;  therefore,  if  he  fails  to  show  an  increase  it  tends  to 
throw  him  into  the  next  younger  class,  and  is,  therefore,  a 
symptom  of  strength,  or  it  may  be  one  of  many  symptoms  of 
great  weakness.  The  way  we  differentiate  the  complication  is, 
if  a  big,  strong-looking  fellow  shows  6.00  or  7.00  D.  accommo- 
dation at  the  first  test,  we  know  he  is  extra  strong  and  do  not 
expect  any  increase  later,  but  if  he  starts  in  with  only  3.00  D., 
4.00  D.  or  5.00  D.  and  appears  to  be  presbyopic  after  correc- 
tion so  that  he  accepts  addition  for  reading,  yet  is  below  forty- 
five  years  old,  we  take  it  as  a  symptom  of  weakness  worth 
more  than  a  half  dozen  sjonptoms  of  strength,  and  we  order 
rest  instead  of  adding  for  reading.  This  is  of  course  subject 
to  modification  if  the  patient  has  been  wearing  glasses  con- 


CLINICAL  HINTS.  175 

stantly  and  the  nature  of  his  work,  habits,  etc.,  has  been  such 
as  to  produce  presbyopia  prematurely. 

Briefly,  if  any  one  of  these  classes  shows  symptoms  of  the 
next  older  class  it  means  weakness,  and  if  he  shows  those  of 
the  next  younger,  it  means  strength.  Of  course  the  first  class 
have  no  younger  class  and  can  go  wrong  only  one  way,  while 
the  middle  class  can  go  both  ways,  as  can  also  the  third  class, 
because  there  is  still  a  fourth  in  which  the  weakness  exhibited 
is  from  natural  presbyopia. 

There  are  other  ways  in  which  the  dynamic  tests  are  valu- 
able, which  are  set  forth  in  the  neurometsr.  First,  when  we 
make  the  first  dynamic  test  we  form  a  diagnostic  opinion  by 
combining  it  with  the  general  appearance  and  history  of  the 
patient.  Thus,  if  a  child  under  twenty  years  shows  only  6.00 
D.  or  7.00  D.  accommodation,  we  know,  looks  or  no  looks,  that 
it  is  in  a  bad  fix,  but  if  it  shows  11.00  D.  or  12.00  D.,  when  we 
think  it  ought  to  show  14.00  D.  we  conclude  it  is  either  weak 
or  is  overcoming  a  great  deal  of  hyperopia,  and  it  amounts 
to  a  symptom  of  weakness  in  either  case,  which  makes  us 
wary.  Or,  if  we  find  7.00  D.  in  a  person  whom  we  think  ought 
to  show  10.00  D.,  it  is  a  caution  signal,  although  we  may  find 
the  patient  older  than  we  think,  and  if  we  do,  it  is  a  reassuring 
symptom. 

Sometimes  as  a  matter  of  proof  of  our  system  we  first  take 
the  dynamic  test,  then  put  on  a  pair  of  4-  3.00  spheres  and  re- 
peat the  test,  then  ask  the  patient's  age.  From  this  data  we 
proceed  to  figure  out  the  amount  of  error  that  should  be  pres- 
ent. Thus  a  case  showed  by  the  first  test  31/2  inches  or  11.00 
D.  Adding  4-  3.00  D.  and  repeating  the  test  he  shows  21/2 
inches  or  16.00  D.  Subtracting  the  +  3.00  from  this  leaves 
13.00  D.  to  be  credited  to  him ;  hence  if  he  had  13.00  D.  power 
with  which  he  showed  only  11.00  D.  he  must  have  been  over- 
coming 2.00  D.  hyperopia;  or,  after  finding  the  13.00  D.  which 
indicates  12  years,  6  months  by  the  neurometer,  we  added  10 
years  for  mentality,  which  brought  it  up  to  22  years,  6  months, 
then  we  asked  his  age,  which  was  29  years,  5  months,  8  days. 


176  OPTICAL   TRUTHS. 

The  difference  between  this  and  22  years,  6  months,  equals  6 
years,  11  months,  8  days.  The  nearest  to  this  amount  shown 
by  the  neurometer  is  6  years,  3  months  for  1.75  hyperopia,  or 
7  years,  6  months  for  1.50  hyperopia.  We  chose  the  former 
because  it  is  nearer  to  the  result  of  the  short  calculation. 
Hence  by  one  calculation  we  found  he  should  have  2.00  D. 
hyperopia  and  by  the  other  1.75  D.  hjrperopia.  Of  course  this 
being  found  by  the  dynamic  test  alone  was  not  as  reliable  as 
if  we  had  completed  the  analysis,  nor  could  we  find  astigma- 
tism by  this  method,  but  it  is  one  of  the  many  things  that  go  to 
make  up  the  proof  of  the  accuracy  of  our  methods.  A  com- 
plete test  of  this  case  found  2.00  D.  hyperopia. 

Another  dynamic  feature  in  symptomatology  is  found  in 
the  reactions  of  the  dynamics  during  the  refraction  test.  If 
the  patient  sees  better  one  moment  than  another  with  the  same 
lenses,  or  if  he  improves  a  certain  amount  with  a  —  .50  in 
front  of  the  fogging  lens  and  then  requires  more  than  that  to 
improve  an  equal  amount  more,  clonic  spasm  is  indicated,  or 
if  he  improves  as  much  with  a  less  amount  of  lens  it  also  indi- 
cates clonic  spasm,  but  at  the  same  time  we  caught  it  on  the 
reaction;  but  if  in  connection  with  the  first  named  symptom, 
that  is,  seeing  better  one  minute  than  another  with  the  same 
lens,  there  is  also  nausea  on  the  down  turn,  it  signifies  general 
weakness. 

Another  form  of  dynamic  test  is  developed  subjectively 
by  cross-questioning.  If  a  patient  has  a  dry,  itchy  eye  or  dif- 
ficult urination,  or  dysmenorrhoea,  or  piles,  or  even  finds  it 
difficult  to  swallow,  they  are  symptoms  of  irritation,  and  we 
call  them  +  because  they  signify  sphincter  contraction  or 
spasm. 

If  the  eyes  are  overflowing  with  tears  or  there  is  urinal 
incontinence,  or  if  the  menses  are  too  frequent,  even  if  there 
is  dysmenorrhoea,  or  if  there  is  constipation  with  a  combina- 
tion of  other  —  symptoms,  we  know  that  it  is  due  to  nervous 
inability  and  that  there  is  danger  of  a  general  paralysis. 

Acute  headache  means  spasm,  but  when  they  reach  the 


CLINICAL  HINTS.  177 

stage  of  sick  headache  it  means  exhaustion  of  the  general  sup- 
ply. Dull,  continuous  headaches  indicate  an  overworked  liver 
and  a  consequent  weakness  of  the  nerve  supply ;  but  this  symp- 
tom is  rather  one  of  caution  and  a  suggestion  to  remove  the 
pressure  in  order  to  find  whether  it  is  genuine  weakness  or 
only  a  temporary  disability.  In  such  cases  as  this  it  is  best  to 
demand  a  good  fee,  because  while  it  may  be  temporary,  hence 
quickly  repaired,  it  is  just  as  liable  to  be  a  chronic  case.  Of 
course  we  form  final  judgment  by  the  general  appearance,  his- 
tory, static  tests,  and  the  final  analysis. 

The  first  static  test  is  that  in  which  we  delve  into  the  his- 
tory of  the  case,  and  as  we  also  get  some  dynamic  information 
from  the  history  we  must  learn  to  separate  the  static  from  the 
dynamic  symptoms  as  we  go.  For  example:  A  patient  tells, 
with  reference  to  his  occupation,  that  he  does  certain  things, 
and  the  fact  that  he  does  them  proves  that  he  must  have  con- 
siderable force  at  his  command,  but  when  we  ask  him  how  he 
feels  afterward  and  he  says  "It  knocks  me  out,"  it  becomes 
a  static  symptom  of  weakness  which  overbalances  the  other; 
then  the  two  together  form  another  symptom  which  tells  us 
that  his  mentality  is  a  dominating  element  which  must  be 
considered  in  the  final  calculation  in  figuring  his  age.  Of 
course  we  must  also  find  how  quickly  he  recuperates  after 
these  excesses,  and  if  for  instance  he  wakes  up  refreshed  the 
next  morning,  it  is  a  -|-  symptom,  while  if  he  is  still  tired  it 
is  a  —  symptom. 

Again,  if  a  patient  does  not  report  doing  things,  but  on 
the  contrary  is  doing  practically  nothing,  yet  complains  of  a 
constant  weariness,  it  is  a  bad  negative  symptom;  this  is  par- 
ticularly true  of  young  women,  and  it  is  quite  common  among 
them;  and,  for  tlie  reason  it  is  rare  among  young  men,  it  is 
serious  when  we  find  it. 

Objectively  the  ophthalmoscope  is  a  static  test  by  which 
we  ascertain  the  nourishing  quality  of  the  blood,  knowing  that 
the  arteries  should  maintain  about  80 'T  red  and  have  a  light 
streak  down  the  center,  while  the  veins  should  have  a  darker 


J78  OPTICAL   TRUTHS. 

shade  and  the  streak  be  fainter.  In  anaemia  the  arteries  some- 
times appear  extra  pale  and  the  white  streak  occupies  2/3 
instead  of  1/3,  the  veins  appear  still  darker  and  the  contents 
more  like  wet  sugar;  that  is,  there  will  appear  little  globules 
or  sediment. 

Another  static  test  is  with  the  double  prism  and  red 
light.  A  light  being  placed  at  fifteen  or  twenty  feet  should 
appear  as  three,  two  being  seen  by  one  eye  and  one  by  the 
other;  the  latter  should  be  in  the  middle  and  all  on  a  vertical 
line.  If  the  middle  one  is  out  of  line,  the  objects  seen  by  each 
eye  swinging  to  their  respective  sides,  it  proves  weakness,  no 
matter  what  the  dynamic  test  showed;  but  if  the  objects  swing 
to  the  opposite  sides  it  is  proof  of  spasm,  no  matter  what  the 
dynamic  test  showed.  If  the  middle  light  deviates  up  or  down, 
alone  or  in  connection  with  the  out  or  in  turn,  it  simply  means 
a  complication  in  the  nerve  distribution,  which  always  means 
rest.  Of  course  this  test  is  repeated  after  correction  of  error, 
and  if  the  —  indications  are  still  present  it  increases  the  im- 
portance of  the  symptom  with  reference  to  the  final  prescrip- 
tion, and  if  the  +  impulse  still  remains  it  tells  us  we  have  not 
the  full  correction  of  eye  error,  and  we  increase  it  as  indicated 
by  the  neurometer;  if  the  up  and  down  turn  remains,  it  indi- 
cates rest  and  is  a  —  symptom  even  if  it  appears  in  connection 
with  the  ^-  symptom  when  the  lights  cross  over. 


SOME  STATISTICS  OF  AMETROPIA. 

Interesting  Data  Which  Offer  Suggestions  to  the  Ambitious 

Practitioner. 
As  the  two  greatest  faults  among  oculists  and  opticians 
are  that  they  rarely  get  on  enough  +  and  often  give  too  much 
—  lenses,  the  following  statistics  are  given  just  as  they  come 
from  my  files,  and  are  the  findings  in  428  consecutive  cases 
aggregating  856  eyes: 

Simple  hyperopia,  387,  or  about  45  per  cent. 

Compound  hyperopia,  287,  or  about  33  per  cent. 

Simple  hyperopic  astigmatism,    44,  or  about     5  per  cent. 

Simple  myopia,  41,  or  about    5  per  cent. 

Compound  myopia,  32,  or  about    4  per  cent. 

Simple  myopic  astigmatism,  7,  or  about    1  per  cent. 

Mixed  astigmatism,  58,  or  about    7  per  cent. 

Exactly  50  per  cent  were  astigmatic.  Of  these  428  eyess 
there  were,  of 

Simple  hyperopic  astigmatism,  44,  or  about  101/2  per  cent. 
Compound  hyperopic  astigma'm,  287,  or  about  67  per  cent. 
Simple  myopic  astigmatism  7,  or  about    11/2  per  cent. 

Compound  myopic  astigmatism  32,  or  about  71/2  per  cent. 
Mixed  astigmatism,  58,  or  about  131/2  per  cent. 

In  nearly  all  cases  there  was  the  so-called  muscular 
imbalance,  which  disappeared  soon  after  the  correction  of  the 
errors ;  some  at  once.  Of  course,  in  addition  to  correcting  the 
eyes,  rest  and  regulation  of  habits  was  required  for  the  worst 
cases.  About  80  per  cent  showed  exophoria  (the  other  fellow 
called  it  esophoria),  and  the  rest  were  either  orthophoric  or 
exhibited  esophoria  (the  other's  exophoria). 

Of  161  pairs  of  +  spheres  prescribed,  27  were  weaker  than 
-f  1.00 ;  85  were  +  1.00  to  +  1.75 ;  35  were  +  2.00  to  +  2.75 ; 
8  were  -f  3.00  to  +  4.00 ;  6  were  +  4.00  to  +  11.00.  Of  these 
161  persons,  25  were  anisometropes. 


J8C  OPTICAL   TRUTHS. 

In  18  pairs  of  —  spheres  2  were  —  .50;  1  —  2.50;  2  — 
3.50;  1  —  4.00;  2  —  5.00;  and  10  were  anisometropes. 

In  37  cases  of  oblique  hyperopia  astigmatism  25  required 
-J-  compounds  for  both  eyes ;  11  required  1  4-  compound  and  1 
sphere;  and  1  took  1  ^  compound  and  1  cylinder.  Of  those 
needing  a  sphere  for  one  eye,  6  were  on  the  left,  and  5  on 
the  right. 

In  8  cases  of  oblique  myopic  astigmatism  4  required  — 
compound  for  both  eyes;  3  took  —  compound  and  —  sphere; 
1  took  —  compound  and  —  cylinder. 

There  were  4  cases  of  simple  hyperopic  astigmatism  with 
oblique  axes. 

In  19  cases  of  mixed  astigmatism  with  oblique  axes  11 
required  compound  for  both  eyes;  4  took  1  compound  and  -f- 
sphere ;  4  took  1  compound  and  1  -f-  cylinder. 

In  133  cases  of  compound  hyperopia  axes  90  or  180,  92 
required  compound  for  both  eyes ;  34  took  1  compound  and  + 
sphere ;  7  took  1  compound  and  1  cylinder.  Of  those  requiring 
spheres  for  one  eye  18  need  it  on  the  left  and  16  on  the  right. 

In  14  cases  of  compound  myopia  axes  90  or  180,  6  re- 
quired compounds  for  both  eyes;  6  used  a  —  sphere  in  one 
eye;  2  used  +  sphere  in  one  eye. 

In  12  cases  of  simple  hyperopic  astigmatism  9  required 
cylinders  for  both  eyes ;  3  took  +  spheres  in  one  eye. 

In  18  cases  of  mixed  astigmatism  axes  90  or  180,  10  re- 
quired compound  for  both  eyes;  5  took  1  compound  and  1  -j- 
sphere;  2  took  1  compound  and  1  +  cylinder;  1  took  1  com- 
pound and  1  —  cylinder. 

Of  the  428  cases,  20  were  boys  under  sixteen  years;  82 
were  girls  under  twenty;  155  were  women;  171  were  men. 


CYCLOPLEGICS,   MYDRIATICS,   MYOTICS. 

Something  About  Drugs  for  Which  the  Neurologist  Has,  Oc- 
casionally, a  Little  Use. 

Cycloplegics  are  drugs  which  dilate  the  pupils  of  the  eyes 
and  break  down  spasm  of  the  ciliary  nerves.  Mydriatics  are 
those  which  only  dilate  the  pupils.  Those  commonly  used 
are:  (1),  Atropine,  an  alkaloid  of  Atropa-Belladonna,  or 
Deadly  Night-shade;  (2),  Homatropine,  a  product  of  Atropine; 
(3),  Duboisine,  from  Duboisia  Myoporoides;  (4),  Hyoscamine, 
or  Scopolomine,  from  Scopolia  Japonica;  (5),  Daturine,  from 
Daturia  Stramonium;  (6),  Gelsemine,  from  Gelsemium  Sem- 
pervirens;   (7),  Cocaine,  from  Erythroxlyin  Coco. 

Those  in  most  common  use  are  Atropia-sulphate  and  Sco- 
polamine. They  are  often  used  in  solution  of  2  to  4  per  cent. 
The  objections  to  their  use  are:  (1),  the  length  of  time  re- 
quired to  secure  complete  mydriasis;  (2),  the  discomfort  to 
the  patient  from  the  effect  on  the  general  system  which  it 
enters  via  the  tear-duct  through  the  nose  and  throat;  (3),  it 
does  not  keep  longer  than  a  couple  of  weeks;  (4),  the  dose  is 
unavoidably  inaccurate  as  to  strength. 

Homatropine,  combined  with  Cocaine,  and  put  up  in  gel- 
atin disks,  is  the  most  satisfactory  of  all  because  (1),  the  accu- 
racy of  the  dose;  (2),  it  keeps  indefinitely;  (3),  it  acts 
quickly;  (4),  there  is  alDsolutely  no  danger  in  its  use. 

The  disks,  as  put  up  by  chemists,  and  kept  by  all  whole- 
sale drug  and  optical  houses,  are  in  iDone  boxes  or  glass  bot- 
tles, each  containing  fifty  disks..  The  stock  numbers  of  the 
ones  most  used  are: 

No.  338  Homatropine  and  Cocaine,  1/50  grain  of  each  in 
each  disk.  One  disk  in  each  eye,  under  the  upper  lid  (which 
should  be  everted  and  the  disk  placed  on  the  conjunctiva,  so 
it  will  be  above  the  apex  of  the  cornea),  will  smart  slightly 
for  a  few  moments,  during  which  time  the  eyes  should  be  kept 


J52  OPTICAL   TRUTHS. 

closed;  after  twenty  minutes  the  pupils  will  dilate,  and  in 
about  one  hour  the  patient  should  be  unable  to  read  ordinary 
print  at  any  distance,  but  it  does  not  totally  paralyze  the  ac- 
commodation as  I  have  shown  elsewhere  in  this  book.  The 
effects  pass  away  in  about  twelve  to  twenty-four  hours,  and 
there  are  none  of  the  after-effects  which  are  so  common  in  the 
Use  of  the  solutions. 

No.  336  Homatropine  1/500  grain,  is  used  as  the  other; 
dilates  the  pupil  for  ophthalmoscope  examinations,  and  may 
be  used  on  old  people  to  enable  the  physician  to  examine  cat- 
aracts in  order  to  ascertain  their  condition. 

No.  323  cocaine  muriate,  is  a  local  anesthetic,  used  to 
deaden  the  conjunctiva  while  foreign  bodies  imbedded  therein 
are  removed.  Takes  effect  in  about  six  minutes,  and  passes 
off  in  about  twenty  minutes;  dilates  pupil  for  several  hours. 
As  soon  as  smarting  ceases  after  inserting,  go  to  work  on  the 
object. 

Myotics  produce  artificial  stimulation  to  the  sphincter 
muscles.  Those  most  used  are  Eserine,  Calabarine  and  Physos- 
tigmine,  all  Alkaloids  of  Calabar  Bean. 

No.  331  Eserine  1/1000  grain  to  the  disk  is  used  as  the 
others,  except  for  the  opposite  effect.  In  some  instances  of 
irititis  with  spasm  of  accommodation  there  is  danger  of  the 
iris  adhering  to  the  lens,  and  if  it  does.  Atropine  is  used  to  pull 
it  loose  alternating  it  with  Esrine  to  prevent  mutilation  of 
the  membranes.  Again,  in  myosis,  or  enlarged  pupil  from  inac- 
tion the  sphincter  muscles  of  the  iris,  Eserine  is  used  in  the 
effort  to  stimulate  it  to  action. 

They  are  worthless  except  in  tonic  spasm  where  there  is 
danger  of  adhesion  of  iris  and  lens,  or  where  the  cocaine  is 
necessary  to  permit  the  removal  of  foreign  bodies.  I  have 
never  had  occasion  to  use  a  myotic. 


COLOR  IGNORANCE  AND  BLINDNESS. 

The  First  Named  Is  Very  Common,  While  the  Other  Is  Ex- 
ceedingly Rare. 

A  practical  test  of  color  perception  is  to  ask  a  great  many 
people  to  name  the  color  nearest  white  and  keep  a  record  of 
the  replies.  It  will  be  found  that  men  and  boys  know  very 
little  of  colors  and  tints,  while  women  and  girls  are  usually 
well-informed;  but  even  among  the  latter  will  be  found  many 
who  insist  that  pale  yellow  or  cream-color  is  the  nearest  white, 
when  the  fact  is  pale  green  is  correct,  because  green  is  the 
central  color  of  a  spectrum ;  pale  blue  is  below  it  and  pale  yel- 
low above,  if  the  prism  which  separates  the  elements  is  base 
down.  Pale  blue  is  where  the  lower  dominates  and  pale  green 
is  where  the  central  color  prevails,  hence  the  difficulty  in  dis- 
tinguishing between  the  two. 

No  test  for  color-blindness  is  complete  until  a  persistent 
effort  to  educate  the  subject  fails.  Of  course  there  are  cases 
so  well-defined  that  it  would  be  safe  to  bet  they  could  not  be 
educated,  but  I  have  seen  such  who  learned  readily  after  cor- 
rection of  errors  in  their  dioptric  systems.  That  there  are 
genuine  cases  of  absolute  color-blindness  has  been  proved 
abundantly,  and  of  course  the  phenomenon  calls  for  explana- 
tion. The  old  propositions  that  the  rods  and  cones  of  the 
retina  have  to  do  with  it  by  possessing  three  sets  of  color- 
perceiving  elements,  red,  green,  and  blue  or  violet,  and  that 
there  exist  three  different  visual  substances,  red-green,  blue- 
yellow  and  white-black  appear  fallacious  to  me  because  I  am 
sure  the  consciousness  of  vision  is  not  in  the  retina  any  more 
than  it  is  in  the  cornea  or  lens,  because  the  so-called  dioptric 
system  simply  causes  an  image  to  be  formed  on  the  retina 
which  transmits  the  impressions  to  the  brain  much  after  the 


184  '  OPTICAL  TRUTHS. 

same  fashion  a  counting  machine  registers  on  paper  in  its  in- 
terior the  effects  of  pressing  on  external  keys. 

In  the  physical  portion  of  this  work  I  have  shown  how  an 
aplanatic  lens  is  constructed  and  how  the  combination  over- 
comes chromatic  and  spherical  aberrations.  Natural  philos- 
ophy teaches  that  there  is  nothing  artificial  that  has  no  original 
in  Nature,  therefore  in  looking  about  for  the  original  aplanatic 
lens  we  find  it  in  the  crystalline  humor  of  the  eye;  while  its 
structure  is  liquid  it  is  striated,  like  an  onion,  beginning  with 
a  bi-convex  nucleus  it  is  completed  with  negative  menisci,  the 
whole  forming  a  bi-convex  lens  enclosed  between  the  anterior 
and  posterior  capsules.  As  the  artificial  product  accomplishes 
certain  things,  it  is  reasonable  to  conclude  Nature  made  the 
crystalline  in  the  same  manner  for  the  same  purpose.  I  hold, 
therefore,  that  absolute  color-blindness  is  due  to  the  mal-struc- 
ture  of  the  crystalline. 

One  may  be  absolutely  color-blind  from  abnormal  index  of 
dispersion  in  the  lens,  yet  have  no  errors  of  refraction,  but 
vision  could  not  be  normal  because  of  the  dispersion. 

Other  evidence  that  color  perception  is  a  part  of  the  sen- 
sory nervous  functions  is  that  many  blind  people  have  shown 
their  ability  to  distinguish  color  by  touch.  I  once  knew  a  man 
in  Natchez,  Miss.,  whose  eye-balls  had  been  enucleated  when 
a  child,  who  could,  and  often  did,  tell  the  color  of  different 
roses  by  touching  them  so  lightly  the  petals  were  not  injured. 
He  could  also  tell  the  color  of  one's  hair  in  the  same  manner. 
Others  have  reported  similar  cases. 

One  of  the  most  delicate  corroborations  of  my  duality  dis- 
coveries is  in  this  color  sense.  On  five  pages  following  will  be 
found  the  same  figure  printed  in  different  colors.  The  figures 
are  set  well  toward  the  top  so  the  space  below  can  be  used  for 
the  transfer.  To  try  the  experiment  there  must  be  good  day- 
light and  by  fixing  the  eyes  steadily  on  the  eye  of  the  figure 
for  a  minute  or  two,  then  fixing  on  the  center  of  the  open  space 
below,  the  complementary  color,  or  duality,  will  manifest  itself. 
If  the  figure  observed  is, 


COLOR  IGNORANCE  AND  BLINDNESS.  185 

Black,  white  will  appear. 

Red,  green  will  appear. 

Green,  red  will  appear. 

Yellow,  violet  will  appear. 

Violet,  yellow  will  appear. 
And  if  the  figure  be  in  white  on  a  black  surface,  black  would 
appear  when  the  transfer  of  the  gaze  occurred. 

It  will  be  found  some  people  note  these  changes  quicker 
than  others,  the  complementary  color  often  appearing  as  a 
border  around  the  figure  as  the  eyes  fix  on  it.  Those  who 
are  unable  to  see  the  change  at  all,  even  after  repeated  trials, 
day  after  day,  have  evidenced  that  their  color  perception  is 
not  normal.  But  that  is  not  remarkable  any  more  than  it  is 
that  many  people  cannot  learn  music  or  other  refined  arts 
requiring  delicate  sensory  apparatus. 

In  applying  the  principles  upon  which  I  have  pursued  my 
studies,  the  following  solution  of  color  dualities  presents  itself'. 
All  laws,  or  causes,  are  accompanied,  or  succeeded,  by 
effects.  White  is  a  combination  of  all  colors;  black  is  the 
absence  of  color.  One  is  positive,  the  other  negative  in  nature. 
In  the  spectrum,  we  have  red,  orange,  yellow,  green,  blue, 
indigo  and  violet  as  the  "seven  elementary  colors"  of  accepted 
authorities.  The  red  is  a  decided  element,  while  the  orange 
and  yellow  are  similar,  green  and  blue  are  in  the  same  rela- 
tion, practically,  as  are  also  indigo  and  violet;  therefore  in 
red  and  yellow  we  have  the  -f,  or  acute,  elements,  and  in 
green  and  violet  we  find  the  — ,  or  benign,  elements.  Of  the 
-f,  red  is  the  extreme  and  of  the  —  violet  is.  In  all  positive 
chemical  compounds  the  major  portion  being  -|-  dominates  the 
minor  portion  which  is  — ,  and  in  all  negative  combinations  the 
major  portion  being  —  dominates  the  minor  portion  of  -|-, 
hence  in  the  departures  from  perfect  combinations,  which 
would  form  white,  if  the  major  or  -|-  portion  is  red,  the  minor 
or  —  portion  would  have  to  be  green,  and  if  the  major  por- 
tion is  yellow  the  minor  portion  would,  necessarily,  be  violet. 
Then  it  follows,  as  a  matter  of  course,  that  reversing  the  pro- 


186  OPTICAL  TRUTHS. 

portions  of  elements  would  reverse  the  positions  of  the  prin- 
cipals. The  extreme  -|-  element  combines  with  the  least  — 
and  the  extreme  —  combines  with  the  least  +,  qualitatively, 
and  which  is  to  dominate  in  any  combination  is  a  matter  to  be 
settled  quantitatively. 

The  complementary  relation  between  color  and  sound  is 
illustrated  by  the  red  scream  of  a  frightened  child  and  the 
black  roar  of  thunder. 

That  the  senses  of  smell  and  sound  are  complementary  has 
been  proved  in  the  great  perfumery  houses  of  Detroit,  where 
they  have  what  they  call  the  gamut  of  odors,  regular  musical 
staves,  treble  and  bass,  on  which,  instead  of  notes,  are  writ- 
ten the  names  of  odors.  A  pianist  improvises  a  sweet  little 
melody  and  when  the  odors  corresponding  to  the  notes  are 
combined  in  the  same  proportions  the  decoction  smells  as  it 
sounded  when  it  came  from  the  piano.  I  mention  this  here, 
out  of  place,  because  I  have  no  other  place  for  it  and  it  is  a 
fact  worth  investigating,  particularly  by  those  whose  esthetic 
tastes  are  already  highly  cultivated;  it  would  be  tedious  to 
others. 


PREriXES  AND  SUmXES 


PREFIXES. 

A-,  or  an-,  or  am-,  means  the  same 
as  un-,  in-,  or  im-. 

Ana-,  up,  through,  again. 

Ant-,  or  anti-,  against,  or  opposite  to. 

Apo-,  from. 

Bi-,  two. 

Contra-,   against. 

Dia-,  through. 

Dys-,   difficult,   painful,   defective. 

Ec-,  ecto-,  or  ex-,  away  from,  out- 
side. 

Em-,  en-,  in. 

Endo-,  ento-,  internal. 

Entero-,  intestine. 

Epi-,  upon,  over. 

Extra-,  outside. 

Gastro-,  the  stomach. 

Haema-,  haemo-,  or  haemeto-,  blood. 

Hemi-,  half. 

Hetera-,  abnormal. 

Hydro-,  water. 

Hyper-,  over,  above,  beyond. 

Hypo-,   below. 

Hyster-,  relating  to  the  womb. 

Im,  in-,  negative,  as  impossible  or 
involuntary;  it  sometimes  means 
within. 

Infra-,  beneath. 

Inter-,  between. 

Intra-,  inside. 


Leuco-,  white. 

Lith-,  relating  to  stone. 

Macro-,  large,  to  see  with  naked  eye. 

Melano-,  pigmentation. 

Meso-,  middle. 

Meta-,  after. 

Micro-,    small,    not   visible   to    naked 

eye, 
Mon-,  single. 
Multi-,    Many. 
Myelo-,  referring   to  brain   or  spinal 

cord. 
Myo-,  muscle. 
Neuro-,   nerve. 
Odonto-,  teeth. 
Oligo-,  lack  of. 
Ophthalmo-,  eye. 
Osteo-,  bone. 
Oxy-,  oxygen  or  acidity 
Para-,  through  or  near. 
Peri-,  around. 
Poly-,  many. 
Pro-,  for,  before. 
Pseudo-,   false. 
Pyo-,  pus. 
Pyr-,    or    pyro-,     fire,     inflammation, 

fever. 
Retro-,  backward,  behind. 
Sub-,  under. 

Super-,  or  supra-,  above. 
Sym-,  or  syn-,  together,  the  same. 


188  OPTICAL   TRUTHS. 

SUFFIXES, 
-aemia,  condition  of  blood, 
-agogue,   to  carry  away, 
-agra,  an  attack, 
-algia,  pain. 

-cele,  a  hernia  or  protrusion,  tumor- 
ous, 
-ectomy,  to  cut. 
-graph,  to  write, 
-itis,  inflammation, 
-logy,  discourse, 
-malacia,  soft, 
-mania,  madness, 
-odynia,  pain, 
-oid,  form, 
-oma,  txmior. 

-opia,  relating  to  condition  of  eye.     . 
-pathy,  relating  to  d'iseases  and  their 

cure, 
-phobia,  fear, 
-plasty,  to  form, 
-raphy,  a  suture, 
-rhagia,  to  burst  forth, 
-rhoea,  to  flow, 
-scopy,  to  see. 
-tomy,  to  cut. 
-uria,  referring  to  urine. 


GLOSSARY 


Aberration — Departure   from  normal. 

Absorption — To  take  up. 

Acetabulum — The  cavity  that  re- 
ceives the  thigh  bone. 

Achromatic — Without   color. 

Achromatopsia — Total    color-blind- 
ness. 

Albinism — Absence  of  the  layer  of 
I^igmentum  nigrum  .in  optic 
choroid. 

Anaemia — A   condition  of  wasting. 

Anchylobelpharon  — .A  stiffening  of 
the  eye-lids. 

Aneurism — ^A  wart-like  dilatation  of 
vessels. 

Anisometropia  —  Unequal  vis'ion  in 
one's  two  eyes. 

Anopsia — Without  vision. 

Amaurosis — Obscure  vision. 

Amblyopia — See  Amaurosis. 

Ametropia  —  Imperfect  .refractive 
condition  of  the  eye. 

Aphakia. —  Absence  of  crystalline 
lens. 

Aplanatic — Corrected    rectilinearly. 

Apparent — Something  seen. 

Approximate — Nearly. 

Arcus  Senilis — Senile  ulcer,  degenera- 
tion of  corneal  cells  forming 
gray  crescent  or  circle  at  edge 
of  cornea,  mostly  in  old  people; 
harmless. 


Astigmatism  —  Without  a  point. 
Caused  by  irregularity  of  the 
curvature  or  the  refracting 
media. 

Asthenopia  —  Fatigue  of  ocular 
nerves,  neurasthenia. 

Atrophy — Loss    of   vitality,    wasting. 

Biliary — Referring  to  the  liver. 

Binocular — Two-fold  vision.  To  see 
with  both  eyes  at  once. 

Blepharitis  —  Inflammation  .  of  the 
eyelids. 

Bulimia  — .Morbid  hunger.  Occurs 
after  eating  too  much;  is,  in 
fact,  nature  calling  for  help  to 
digest  what  is  in  the  stomach.. 

Canthi  (s,  canthus) — Angles  formed 
by  the  upper  and  lower  eyelids, 
from  the  middle  to  either  side. 

Combination — A  union  of  parts. 

Centripetal — Tending  toward  a  cen- 
ter. 

Centrifugal — Tending  from   a   center. 

Convergent — Two  or  more  lines  in- 
clined toward  a  point. 

Chromatic — Pertaining    to    colors. 

Conjugate — Yoked   together. 

Cylindrical — Like  a  cylinder. 

Catoptrics. —  Laws  of  reflection  of 
light. 

Chalazion — Tumor  of  the  eyelid. 

Chromatopsia — Abnormal  color  sense. 


190 


OPTICAL   TRUTHS. 


Cilia — The  eyelashes. 

Ciliary  Body — Apparatus  of  accom- 
modation. 

CoUyrium — An   eye-wash. 

Coloboma — A  mutilation. 

Conjunctiva— To  join  together.  The 
transparent  membrane  which 
lines  the  lids  and  covers  the 
front  of  the  eyeball. 

Conjunctivitis — Inflammation  of  con- 
junctiva. 

Corectopia — Pupil  out  of  place. 

Coredialysis — A  rupture   of  the  iris. 

Cornea — Horny  —  The  projection  on 
the  front  of  the  globe. 

Cyclitis — Inflammation  of  the  ciliary 
body. 

Cycloplegiia — Paralj'sis  of  the  ciliary 
muscles. 

Cycloplegics — Drugs  which  paralyze 
the  accommodations. 

Disintegration — Separating    parts. 

Divergent — Two  or  more  lines  radi- 
ating from  a  point. 

Dispersion — To    scatter. 

Density — Compact. 

Diaphanous — Transparent. 

Duality — Double. 

Dacro-cyst'itis — Inflammation  of  the 
lachrymal  sac. 

Daltonism — Color-blindness. 

Dioptre — To  see  through —  a  unit  of 
measure  in  optics;  one  metre. 

Diplopia — Double  vision. 

Dynamic — Force. 

Ecchymosis — Black  eye. 


Ectopia — Partial  luxation  of  the 
crystalline. 

Ectropion — Everslon  of  eyelids. 

Emmetropia — A  perfect  condition  of 
the  refracting  media. 

Embolism — A  plugging. 

Entropion — Inversion   of   eyelids. 

Entozoa  —  A  worm-like  parasite, 
which  finds  its  way  into  almost 
any  portion  of  the  eye,  and  de- 
stroys tissue  by  causing  small 
cysts. 

Enucleate — To  remove. 

Epiphora — Overflow  of  tears. 

Esophoria — Convergence  of  visual 
axes. 

Essential — Necessary, 

Equ'ivalent — Equal  in  value. 

Exophoria  —  Divergence  of  visual 
axes. 

Exophthalmos  —  Abnormal  promi- 
nence of  eyeballs.  Grave's  dis- 
ease. 

Foramen — A  passage  or  opening. 

Fossa — A  ditch. 

Fundus — Bottom. 

Finite — Having  a  limit. 

Formula — A  form. 

Glaucoma — Green;  a  disease  of  the 
ciliary  processes  and  optic  nerve. 

Glioma — Glue. 

Hypothesis — A  supposition  assumed 
for  the  purpose  of  presenting  an 
argument. 

Horizontal — From  horizon  to  hori- 
zon. 


GLOSSARY 


191 


Hemiopia — Half  vision. 

Hemeralopia — Day   blindness. 

Heterophoria — An  abnormal  muscu- 
lar condition. 

Heterophthalmos — Congenital  differ- 
ences of  color  in  the  iris,  or  of 
two  eyes. 

Hippus — Alternate  contraction  and 
expansion  of  pupil. 

Hordeolus — A  style. 

Horopter — The  field  of  vision  includ- 
ed by  both  eyes  at  once,  with- 
out moving. 

Hyaloid — Glass-like;  a  thin  mem- 
brane which  lines  the  inner  sur- 
face of  the  eye. 

Hyalitis — Inflammation  of  the  vilr" 
ous. 

Hyperphoria — One  optical  axis  tends 
above  the  other. 

Hypopyon — An  abscess  from  corneal 
ulcers. 

Inverted — Upside  down. 

Index — A  pointer. 

Iridectomy — A  cutting  of  the  iris. 

Iridodialysis — Separation  of  iris  from 
diliary  body,  as  a  result  of  blows. 

Iridodonesis — Trembling  of  the   i- 

Iris  (a  rainbow) — The  colored  por- 
tion of  the  eye  surrounding  the 
pupil. 

Iritis — Inflammation   of  the  iris. 

Jugular — Pertaining  to  the  throat. 

Jurisprudence — Relating    to    law. 

Keratitis. —  Inflammation  of  the 
cornea. 


Keratokonus — Conical  shape  of  the 
cornea. 

Keratonyxis — Puncture  of  the  cor- 
nea. 

Luminous — Emitting  light. 

Leucoma — White. 

Leucorrhoea — White,   to   flow. 

Lagophalmos — Inability  to  close  the 
eyelids. 

Locomotor  Ataxia  —  Creeping  pa- 
ralysis. 

Metaphysics  —  Pertaining  to  the 
mind.    After  physics. 

Meridian — A  line  drawn  from  one 
side  of  a  circle  to  the  other 
through  the  center. 

Meter — Measure. 

Macula — Spot.  The  field  of  sharpest 
vision. 

Malingerer — One  who  falsely  pretends 
to  have  an  incurable  defect  of 
vision,  or  other  function,  to  ex- 
cite sympathy  or  evade  duty. 

Metamorphopsia — Distorted   vision. 

Migraime — Sick    headache. 

Muscae  Volitantes — Floating  specks 
in  the  eye. 

Mydriatics — Drugs  which  dilate  the 
pupils. 

Myopia — To  close  the  eye. 

Myotics — Drugs  which  stimulate  the 
accommodation. 

Neurology — The  science  which  treats 
of  the  nervous  system. 

Negative — Opposed    to    positive. 

Nodal  Point — A  center  of  curvature. 


192 


OPTICAL   TRUTHS. 


Nebula — A  cloud. 

Nephritis — Inflammation    of    kidneys. 

Neuritis — Inflammation  of  the  optic 
nerve. 

Nictitation — To   wink. 

Nystagmus — A  jerking  of  the  eye- 
balls. 

Nyctalopia — Night    blindness. 

Oblique — Slanting. 

Oedema — An  exudation. 

Ophthalmia  —  Inflammation  of  the 
eyes. 

Ora  Serrata  —  Serrated  boundary. 
The  dircle  of  connection  between 
the  retina  and  ciliary  processes. 

Orthophoria — Normal  muscular  con- 
ditions. 

Ophthalmology — The  science  which 
treats  of  the  eyes. 

Ophthalmoplegia  (interna  and  ex- 
terna)— Paralysis  of  the  sphinc- 
ter muscles  of  pupils  and  ciliary; 
usually  from  the  use  of  cydo- 
plegics. 

Parallel — Two  lines  constantly  at 
equal  distance  from  each  other. 

Perpendicular — At  right  angles  to. 

Positive — Absolute,  direct. 

Physics — Natural    philosophy. 

Piano— Flat. 

Palpebrae — The    eyelids. 

Pannus  —  Corneal  vascularization 
from  long  continued  irritation. 

Papilla — A  nipple.     The  optic  disk. 

Phakatis — Inflammation  of  the  lens. 

Phlyctenule — A  pimple. 


Photophobia — Aversion  to  light. 

Pinguecula — A  small  elevation  on  the 
ocular  conjunctiva;  sometimes 
mistaken   for  pterygium. 

Posterior  Synechia — Adhesion  of  iris 
to  lens. 

Presbyopia — Old  sight. 

Pterygium — A  little  wing.  Is  a  hyper- 
trophy of  the  conjunctiva  and 
grows  on  sclerotic  and  cornea, 
sometimes  interfering  with 
vision.    May   be   removed. 

Ptosis — A  falling  of  the  upper  lid 
from  weakness  of  the  third 
nerve. 

Retina — A  net.  The  visual  membrane 
of  the  eye. 

Repulsion — To  drive  away. 

Refraction — To  break. 

Reflection — To  turn  b^ck. 

Right   Angle — Perpendicular. 

Respective — With  reference  to. 

Reversed — Turned  around. 

Spectral — Refers  to  colors  found  by 
separation  of  a  ray  of  light  into 
its  elementary  colors  by  a  prism. 

Symbol — Having    resemblance. 

Spherical — Like  a  sphere  or  globe. 

Segment — A  slice. 

Sclerosis — Hardening. 

Sclerotic— Hard.  The  white  of  the 
eye. 

Scotoma  — .Obstruction,  of  .vision 
from  hemorrhages.    Darkness. 

Strabismus — To   squint. 

Stroma — Bedding. 


GLOSSARY 


J93 


staphyloma — A  bulging  projection. 
Anterior,  comes  after  corneal  ul- 
cers, and  is  a  bluish-wMte  in  ap- 
pearance. Posterior,  is  a  pro- 
jecting backward  of  the  posterior 
pole  of  the  eye. 

Supercilium — The    eyebrows. 

Symblepharon — Adhesion  of  ocular 
and  palpebral  conjunctiva,  caused 
by  escharotics,  such  as  lime, 
ashes  or  other  alkalies. 

Synechia — To  hold  together. 

Synchisis — To  flow  together. 

Transparent — Passes  light  so  objects 
can  be  seen. 

Translucent — Passes  light,  but  ob- 
jects cannot  be  seen. 

Tapetum — A   carpet. 

Tension — The  condition  of  an  organ, 
muscle  or  nerve  when  under 
strain. 

Thrombosis — A  plugging  of  retinal 
vessels  by  blood  clots.  Some- 
times causes  hemorrhages  which 
bring  at  least  temporary  blind- 
ness. 


Trachoma — (Rough).     Granular    con- 
junctivitis. 
Trauma — A  wound. 
Tinea    Tarsi — Eczema    of    border     of 

lids. 
Urea — The  chief  solid  constituent   of 

urine. 
Uveal    Tract — The    choroid,    iris    and 

ciliary  body  of  the  eye. 
Vertical — Straight   up    and   down. 
Virtual — Existing  in  effect. 
Vesicular — Bladder-like. 
Vascular — Pertaining  to    vessels. 
Vitreous — Glass-like. 
Xanthelasma  —  Yellow     patches     of 

fibrous  tissue  on  the  lids,  mostly 

of   women.     Harmless,   but    may 

be  removed. 
Xerophthalmus — Dry  eye. 


Neurology  and  Metaphysics 

By  Charles  McCor/nick,  M.  D. 

Contains  pradically  all  that  is  in 
"Optical  Truths,"  and  goes  into 
Anatomy,  Physiology,  Neurology 
Metaphysics,  Etc.,  in  such  de- 
tail, yet  so  very  comprehensively 
that  it  is  receiving  high  compli- 
ments   from    all    purchasers 


II 


Price  $20.  Less  $3  to  pur- 
chasers of  "Optical  Truths." 
Remit  by  Draft  or  Money 
Order.        No    Checks.         To 

McCormick  Neurological  College 

Chicago,  U.  S.  A. 


McCORMICK 
NEUROLOGICAL  COLLEGE 

THE  FIRST  NON-SECTARIAN 

MEDICAL  SCHOOL. 

FOUNDED  1893 


QUALIFIES   its  students  to  analyze  conditions, 
remove   causes   and    thus  let   Nature  cure   the 
"chronics"  and   "incurables"   of   old-school    practice. 

POST-GRADUATE     COURSE     FOR 
PHYSICIANSJWO  MONTHS,  $200 

GENERAL   COURSE  FOR  UNDER- 
GRADUATES, SIX  MONTHS,  $500 

NO  other  school  in  the  world  teaches  what  we  do, 
although  many  imitations  have  been  launched 
by  cheap  people  who  have  a  mistaken  idea  about  grow- 
ing rich.  All  this  school  makes  goes  to  enlarging  its 
facilities.  ^  In  taking  up  a  life  work  prospective  stu- 
dents are  advised  to  investigate  personally.  ^Anyone 
who  takes  any  of  our  courses  and  is  not  satisfied,  will 
receive  the  tuition  fee  for  the  asking. 

McCoRMicK  Neurological  College, 

Chicago,  Illinois,  U.  S.  A. 


THE 

OPHTHALMOLOGIST 

a    MONTHLY    MAGAZINE 

CHARLES  Mccormick,  M.D.,  Editor 

ESTABLISHED  JANUARV,  190  O 


A  TERROR  TO  RASCALS 


SUPPORTER  OF  HONESTY 


SEARCHER  EOR  TRUTH 


NEMESIS  OF  VACCINATION 


FIGHTS  MEDICAL  TRUSTS 


A  JOURNAL  OF  PROGRESS 


TWO  DOLLARS  A  YEAR  TWENTY  CENTS  A  COPY 

THE  OPHTHALMOLOGIST 
CHICAGO 


BALE'S  &  TABER'S 

ANATOMICAL  AND  PHYSIOLOGICAL 

Encyclopedic  Chart 
of  the  Human  Body 

FIFTEEN  ILLUSTRATIONS 

LITHOGRAPHED  IN  SEVEN  COLORS 

MOUNTED  LIKE  A  MAP 

ENAMELED  CLOTH  STOCK 

INFORMATION  ON  BOTH  SIDES 

5000  QUESTIONS  ANSWERED 

WORTH  ITS  WEIGHT  IN  GOLD 

SIZE  34x46  INCHES 

Price,  Express  Prepaid 

$5.00 

If  Ordered  with  the  Ophthalmologist  for  One 
Year,  the  Price  for  Both  is  $6.00 


Remit  by  Draft  or  Money  Order 
No  Checks==to 

THE 

OPHTHALnOLOGIST 

CHICAQO,  ILL.,  U.  S.  A. 


Class  Legislation  is  J^  I  ways 
Unconstitutional 


When  a  lot  of  do6lors  secure 
the  passage  of  laws  to  re- 
stri(?t  competition,  that  is 
class  legislation,  hence  void. 
^  The  medical  trust  boasts 
of  its  ability  to  declare  com- 
petitors criminals  by  their 
alleged  laws.  ^  The  dentists 
boast  openly  that  they  have 
it  in  their  power  to  limit  the 
number  of  dentists  in  each 
state  where  they  have  a  law, 
by  making  the  examination 
so  hard  applicants  cannot 
pass.  ^The  opticians  have 
laws  in  a  few  states  and  make 
the  same  boast  the  dentists 
do.  ^  The  whole  proposition 
has  been  made  ridiculous  by 
the  barbers,  the  horseshoers, 
the  plumbers  and  even  the 
undertakers,    who    all   seek 

"proteAion" 

at  the  Publics  Expense 


Vaccination  is  a  Crime 


More  People  Die  from 
Lock-jaw  caused  by  it, 
than  Die  from  Small-pox 


England  repealed  her  compulsory  Vaccina- 
tion Laws  ten  years  ago,  because  the 
vile  stuff  produced  Tuberculosis, 
Cancer,  Erysipelas,  Syphilis 
and   other  loathsome 
disorders. 

The  dodor  who  advocates  it  is  either  an 

Ignoramus  or  a  Scoundrel 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

OPTOMETRY  LIBRARY 

This  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 

Renewed  books  are  subjea  to  immediate  recall. 

LD21 — 32m — 1,'75 
(S3845L)4970 

General  Library 

University  of  California 

Berkeley 

r 


UC  BERKELEY  LIBRARIES 
II                                         1 

II                                         II 

CDESTMSIQT 

y 

n^^(. 

li  331 

Of 


■yo, 


^^ 

ff^ 

\i 

i    ^ 

^ 

T^    1 

rn  1 

v. 

^ 

k 


